Giske Ursin

• Zadnik, V.; Konjević, A. Duratović; Jurtela, M.; Lokar, K.; Bric, N. & Zagar, T. [Show all 22 contributors for this article] (2026). Mapping population-based cancer registries in Europe: coverage, data availability, and capacity for real-world data generation. ESMO Real World Data and Digital Oncology. 14. doi: 10.1016/j.esmorw.2026.100785.
• Johansson, Anna LV; Kønig, Simon M.; Cardoso, Rafael; Møller, Henrik; Ursin, Giske & Skog, Anna [Show all 14 contributors for this article] (2026). Trends in early-onset cancer incidence rates in the Nordic countries (2003–2022): a population-based study. The Lancet Regional Health - Europe. 70. doi: 10.1016/j.lanepe.2026.101858. Full text in Research Archive
• Vandraas, Kathrine Flørenes; Andersen, Sarah Hjorth; Trewin-Nybråten, Cassia Bree; Andreassen, Bettina Kulle; Blix, Egil Støre & Naume, Bjørn [Show all 9 contributors for this article] (2026). Translating CLEOPATRA into routine practice: National treatment patterns and survival for patients with HER2-positive metastatic breast cancer. Breast. ISSN 0960-9776. 89. doi: 10.1016/j.breast.2026.104852. Full text in Research Archive Show summary

  Introduction Amplification of the epidermal growth factor receptor 2 (HER2) gene occurs in 15-20% of breast cancers and was historically associated with poor prognosis. The CLEOPATRA trial established pertuzumab added to trastuzumab and chemotherapy as standard of care for metastatic HER2-positive breast cancer, demonstrating a 15.7-month improvement in median overall survival (OS). Strict trial inclusion criteria may limit generalizability to clinical practice. Population-based data can assess whether these survival benefits translate to real-world outcomes. Methods Women diagnosed with HER2-positive metastatic breast cancer in 2012–2021 were identified through the Cancer Registry of Norway and linked to health and treatment databases. Patients were categorized by treatment regimen and year of treatment initiation: pre-CLEOPATRA (2012–2014; trastuzumab ± chemotherapy) and post-CLEOPATRA (2015–2021; trastuzumab + pertuzumab ± chemotherapy). OS was estimated using Kaplan–Meier and Cox regression adjusted for clinical, and socioeconomic factors. Outcomes were benchmarked against CLEOPATRA. Results The cohort comprised 329 women, 23% were aged ≥65 years. Seventy-eight patients (24%) received pre-CLEOPATRA regimens and 251 (76%) post-CLEOPATRA regimens; 59% met minimum one CLEOPATRA exclusion criterion. First-line dual HER2 blockade increased from 0% in 2012 to 75% in 2021. Median OS improved from 69 months to 96 months post-CLEOPATRA. Four-year OS increased from 59% to 65% (adjusted hazard ratio 0.77, 95% CI 0.53–1.12). Real-world OS was consistent with CLEOPATRA outcomes. Conclusions Nationwide real-world data demonstrate favorable survival outcomes following adoption of dual anti-HER2 therapy. While these findings are broadly consistent with the CLEOPATRA trial, the observational design does not allow direct assessment of equivalence between studies.

• Birkeland, Einar Elvbakken; Kværner, Ane Sørlie; Avershina, Ekaterina; Johannessen, Cecilie Bucher -; Bemanian, Vahid & Blix, Hege Salvesen [Show all 14 contributors for this article] (2026). Microbiome signatures for detection of colorectal lesions in population-based FIT screening. Nature Communications. 17. doi: 10.1038/s41467-026-75962-1. Full text in Research Archive Show summary

  The gut microbiome has been linked to colorectal cancer (CRC) development, with microbe-based classifiers distinguishing between CRC patients and healthy controls. However, there is a lack of studies addressing the utility of the microbiome in screening-relevant settings, including both precancers and CRC. In this Norwegian population-based study, we used fecal immunochemical test (FIT) leftovers from 1034 FIT-positive (i.e. positive for occult blood) screening participants for gut metagenome profiling using shotgun sequencing. Using comprehensive clinical, demographic, and lifestyle data, we modeled gut microbiome associations with CRC screening outcomes. Combining microbial profiles with quantitative FIT values improved detection of premalignant lesions beyond optimizing the FIT value alone, even after incorporating established CRC risk factors. Still, the FIT value maintained superior discriminative ability for CRC. We confirmed enrichment of bacteria such as Fusobacterium nucleatum and Peptostreptococcus stomatis in CRC. In contrast, other bacteria previously associated with the presence of CRC, including Hungatella hathewayi and Clostridium symbiosum, as well as pks-negative Escherichia coli, were enriched in those with no neoplastic findings, suggesting that in a FIT-positive population their presence may reflect other conditions causing intestinal bleeding rather than underlying neoplasia. Microbial profiles were predominantly associated with distal rather than proximal lesions. Together, our findings highlight the potential for microbial markers to improve FIT-based CRC screening, especially by differentiating those with premalignant lesions from those who test FIT-positive for other reasons.

• Morgan, Eileen; Bardot, Aude; Langselius, Oliver; Rutherford, Mark J.; Elkader, Hazem Abd & Bennett, Damien [Show all 47 contributors for this article] (2026). International disruptions to cancer diagnosis and stage at presentation during the COVID-19 pandemic in 2020: an International Cancer Benchmarking Partnership (ICBP) population-based study. The Lancet Oncology. ISSN 1470-2045. 27(6), p. 738–750. doi: 10.1016/S1470-2045(26)00089-6. Full text in Research Archive
• Moshina, Nataliia; Gjesvik, Jonas; Castells, Xavier; Larsen, Marthe; Ursin, Giske & Hofvind, Solveig Sand-Hanssen (2026). Breast cancer mortality among women who have attended BreastScreen Norway, 1996-2023. Breast Cancer Research. ISSN 1465-5411. 28(1). doi: 10.1186/s13058-026-02244-5. Full text in Research Archive
• Yli‐Mäyry, Fernando Gonzalez; Tanskanen, Tomas; Seppä, Karri; Johansson, Anna L. V.; Skovlund, Charlotte Wessel & Mørch, Lina Steinrud [Show all 19 contributors for this article] (2026). Changes in 1‐year relative survival of patients with cancer during the COVID-19 pandemic in Denmark, Finland, Iceland, Norway, and Sweden: A population‐based cohort study. International Journal of Cancer. ISSN 0020-7136. 158(12), p. 3121–3131. doi: 10.1002/ijc.70336. Full text in Research Archive Show summary

  During the first year of the COVID‐19 pandemic, reported cancer cases declined in the Nordic countries, potentially reflecting delays in cancer diagnosis. We compared 1‐year relative survival (RS) and excess mortality of patients diagnosed with cancer in the Nordic countries in March–December 2020 with that expected based on patients diagnosed in 2011–2019. We used flexible parametric RS models, defining excess mortality as the difference in total mortality between patients with cancer and the national population without cancer. We report the ratio between the observed and expected excess mortality (EMR) and the difference in 1‐year RS in percentage points (pp) by country, age, sex, and cancer site. Excess mortality of patients diagnosed during the pandemic was increased in all Nordic countries except Iceland. Swedish men had the highest EMR of 1.12 (95% CI 1.06, 1.17), corresponding to a 1.4 pp reduction in 1‐year RS (87.1%–85.8%). In women, the highest EMR was 1.10 (95% CI 1.03, 1.18) in Norway, corresponding to a 1‐year RS decrease of 1.2 pp (86.6%–85.5%). The largest site‐specific decreases in 1‐year RS were observed for liver cancer in Finnish and Swedish men, with decreases of 10.2 pp (45.3%–35.1%) and 7.2 pp (55.7%–48.5%), respectively. We found reduced 1‐year RS among Nordic patients diagnosed with cancer during the COVID‐19 pandemic in 2020, especially in older patients and those with aggressive cancers. These reductions coincided with restrictions and potential delays in seeking healthcare.

• Larsen, Marthe; Lee, Christoph I.; Bergan, Marie Burns; Holen, Åsne Sørlien; Lund-Hanssen, Håkon & Hoff, Solveig Kristin Roth [Show all 12 contributors for this article] (2026). Performance across different versions of an artificial intelligence model for screen-reading of mammograms. European Radiology. ISSN 0938-7994. doi: 10.1007/s00330-025-12240-6. Full text in Research Archive Show summary

  Abstract Objectives Studies have reported promising results regarding artificial intelligence (AI) as a tool for improved mammographic screening interpretive performance. We analyzed AI malignancy risk scores from two versions of the same commercial AI model. Materials and methods This retrospective cohort study used data from 117,709 screening examinations performed in BreastScreen Norway 2009–2018. The mammograms were processed by two versions of the commercially available AI model, Transpara (version 1.7 and 2.1). The distributions of exam-level risk scores (AI score 1–10) and risk categories were evaluated for both AI versions on all examinations, including 737 screen-detected and 200 interval cancers. Scores between 1–7 were categorized as low risk, 8–9 as intermediate risk, and 10 as high risk of malignancy. Results Area under the receiver operating curve was 0.908 (95% CI: 0.986–0.920) for version 1.7 and 0.928 (95% CI: 0.917–0.939) for 2.1 when screen-detected and interval cancers were considered as positive cases ( p  < 0.001). A total of 87.1% (642/737) and 93.5% (689/737) of the screen-detected cancers had an AI score of 10 with version 1.7 and 2.1, respectively. Among interval cancers, 45.0% (90/200) had AI score 10 with version 1.7 and 44.5% (89/200) had AI score 10 with version 2.1. Conclusion A higher proportion of screen-detected breast cancers had the highest AI score of 10 with the newer version of the AI model compared to the older version. For interval cancers, there was no difference in the proportion of cases assigned to the highest score between the two versions. Key Points Question Studies have reported promising results regarding the use of AI in mammography screening, but comparisons of updated versus older versions are less studied . Findings In our study, 87.1% (642/737) of the screen-detected cancers were classified with a high malignancy risk score by the old version, while it was 93.5% (689/737) for the newer version . Clinical relevance Understanding how version updates of AI models might impact screening mammography performance will be important for future quality assurance and validation of AI models .

• Andersen, Sarah Hjorth; Vandraas, Kathrine Flørenes; Trewin-Nybråten, Cassia Bree; Botteri, E.; Ursin, Giske & Andreassen, Kristoffer Berglund [Show all 7 contributors for this article] (2026). Anti-HER2 treatment in everyday practice: how we treat older women with breast cancer differently. Breast Cancer Research and Treatment. ISSN 0167-6806. 215(2). doi: 10.1007/s10549-025-07888-z. Full text in Research Archive Show summary

  Abstract Purpose Targeted therapies have improved survival in human epidermal growth factor receptor 2 positive breast cancer (HER2 + BC). However, patients over 75 years of age are often excluded from clinical trials of anti-HER2 therapies, and it is unclear to what extent they receive these treatments in routine care. To address this, we examined age-related patterns of anti-HER2 therapy use in real-world clinical practice in Norway. Methods In a nationwide registry-based cohort, we identified women diagnosed with stage I-III HER2 + BC during 2012–2021. We investigated treatment patterns using descriptive statistics and estimated the direct effect of age on anti-HER2 therapy use by Poisson regression. Results Among 3526 women with HER2 + BC, anti-HER2 therapy use was consistently high (83–95%) in those under 75 years, decreased to 60% at ages 75–79, and declined further with advancing age to 8% at ≥ 90 years. Neoadjuvant anti-HER2 therapy also decreased with age (from 24% in patients under 75 to 12% in patients over 75 years). Accounting for cancer characteristics, comorbidities, polypharmacy, and socio-economic factors, older patients had reduced likelihood of receiving any anti-HER2 therapy compared with patients younger than 55 (RR 0.75, 95% CI 0.66–0.85, p < 0.001, at age 75–84 and RR 0.21, 95% CI 0.11–0.41, p < 0.001, at age 85 +). Conclusions Anti-HER2 therapy use declined substantially after the age of 75 even when accounting for comorbidities and polypharmacy. Chronological age appears important in planning treatment for patients with HER2 + BC. Specific guidelines pertaining to older patients with HER2 + BC are needed to avoid potential undertreatment.

• Botteri, Edoardo; Andersen, Sarah Hjorth; Conforti, Fabio; Bagnardi, Vincenzo; Andreassen, Bettina Kulle & Støer, Nathalie Charlotte [Show all 11 contributors for this article] (2025). Aprepitant use during chemotherapy and association with survival in women with early breast cancer. Journal of the National Cancer Institute. ISSN 0027-8874. 117(11), p. 2249–2258. doi: 10.1093/jnci/djaf178. Full text in Research Archive Show summary

  Background Preclinical studies have shown that aprepitant, an antiemetic used to prevent chemotherapy-induced nausea and vomiting, slows mammary tumor growth and progression. Here, we evaluated the association between aprepitant and survival in a large cohort of women with early breast cancer. Methods Using linked nationwide registry data, we identified 13 811 women diagnosed with early breast cancer between 2008 and 2020 in Norway, who received chemotherapy and antiemetics. Women were followed for metastasis and death from 1 year after diagnosis until the end of 2021. To evaluate the association between aprepitant use and distant disease-free survival (DDFS) and breast cancer-specific survival (BCSS), we used Cox regression models, controlling for tumor and patient characteristics, chemotherapy regimens, and use of other antiemetics. Results During chemotherapy, 7047 (51%) women were supplied with aprepitant. Overall, aprepitant use was associated with better DDFS (HRDDFS = 0.89; 95% CI = 0.79 to 1.00) and BCSS (HRBCSS = 0.83; 95% CI = 0.71 to 0.97). The survival advantage was specific to women with non-luminal breast cancer (HRDDFS = 0.69; 95% CI = 0.56 to 0.83; HRBCSS = 0.64; 95% CI = 0.51 to 0.81) and was strongest in women with triple negative breast cancer (TNBC) (HRDDFS = 0.66; 95% CI = 0.53 to 0.83; HRBCSS = 0.61; 95% CI = 0.47 to 0.80). In women with non-luminal breast cancer, longer durations of aprepitant use were associated with increasingly favorable survival outcomes (DDFS: Ptrend = .002; BCSS: Ptrend = .016). Supply of other antiemetics of different drug classes was not associated with survival. Conclusions Aprepitant use during chemotherapy treatment was associated with better prognosis for women with non-luminal early breast cancer, in particular TNBC. Long-term clinical trials are required to confirm these findings.

• Groeneweg, Rick; Ravesteyn, Nicolien T. van; Kregting, Lindy M.; Ursin, Giske; Hofvind, Solveig Sand-Hanssen & Moshina, Nataliia (2025). Quality‐adjusted life years in the presence and absence of organized mammographic screening using data from BreastScreen Norway. International Journal of Cancer. ISSN 0020-7136. doi: 10.1002/ijc.70272. Full text in Research Archive Show summary

  Abstract Benefits and harms of breast cancer (BC) screening with mammography have been debated and, although most studies reported positive effects, some studies found a negative effect in terms of net quality‐adjusted life years (QALYs). We aimed to estimate net QALYs associated with biennial mammographic screening for women aged 50–69 years offered to 100,000 women followed until age 85, using various assumptions on BC mortality reduction, overdiagnosis and mortality transfer (the extent to which a reduction in BC mortality results in a reduction in all‐cause mortality). Individual‐level data from women invited to BreastScreen Norway during 1996–2020 were used to perform the calculations. The three baseline scenarios included (1) Model Microsimulation Screening Analysis (MISCAN): MISCAN prediction for mortality reduction and overdiagnosis proportion; (2) Model A: 40% BC mortality reduction and 15% overdiagnosis; and (3) Model B: 20% BC mortality reduction and 50% overdiagnosis. For all scenarios, an 80% mortality transfer was assumed. An online tool was developed to illustrate the impact of alternative assumptions. Biennial organized mammographic screening for women aged 50–69 years who were followed until the age of 85 years was associated with 6819, 7444 and 2446 net QALYs gained per 100,000 women for Model MISCAN, A and B, respectively. Assumptions on BC mortality reduction exhibited the largest impact on net QALYs. To conclude, even when assuming a high overdiagnosis proportion and low BC mortality reduction, net QALYs remained positive, reinforcing the value of offering BC screening with mammography to Norwegian women and showing its potential to improve health outcomes.

• Svendsen, Karianne; Nes, Lise Solberg; Leithe, Sigrid; Meland, Anders; Gjelsvik, Ylva Maria & Børøsund, Elin [Show all 17 contributors for this article] (2025). Testing two digital stress-management interventions in a randomized controlled trial of breast cancer patients. Scientific Reports. 15, p. 1–16. doi: 10.1038/s41598-025-22889-0. Full text in Research Archive Show summary

  Abstract The digital stress-management intervention StressProffen has been shown to be associated with improved well-being and quality of life for cancer survivors. In the Coping After Breast Cancer (CABC) trial, effects of 6 months’ access to modified versions of StressProffen, delivered through a digital download-only model, were examined. Women with breast cancer were invited to participate in the trial 6–9 months following diagnosis. Eligible participants were randomized to either: (1) digital cognitive behavioral therapy stress-management intervention (CBI), n  = 140, (2) digital mindfulness-based stress-management intervention (MBI), n  = 143, or (3) usual-care (control group), n  = 147. Primary outcome was change in perceived stress level (PSS-10), while secondary outcomes included changes in health-related quality of life (HRQoL), anxiety and depression, fatigue, mindfulness, sleep and coping. Perceived stress level at baseline was low for all groups. No statistically significant mean differences (MD) were detected between either of the intervention groups and the control group from baseline to 6-month follow-up for perceived stress level (MBI: MD -0.28 [95%CI: -1.75, 1.19], CBI: MD -0.42 [95%CI: -1.89, 1.06]), nor for the majority of the secondary outcomes. After 6 months of access, the CBI and MBI stress-management interventions did not yield significantly improved outcomes for women with breast cancer compared with usual-care controls. Further explorations of which interventions and delivery models may optimize use and effect, best timing for delivery, and individual preferences are needed. ClinicalTrials.gov identifier NCT04480203.

• Vandraas, Kathrine Flørenes; Andersen, Sarah Hjorth; Trewin-Nybråten, Cassia Bree; Ursin, Giske; Botteri, Edoardo & Kulle, Bettina [Show all 10 contributors for this article] (2025). Anti‐Her2 therapy patterns in metastatic breast cancer—Real‐world data suggest undertreatment. International Journal of Cancer. ISSN 0020-7136. 158(3), p. 633–641. doi: 10.1002/ijc.70120. Full text in Research Archive Show summary

  Treatment efficacy of anti‐HER2 therapies for metastatic breast cancer (mBC) has been demonstrated in clinical trials, but real‐world data are lacking. In particular, it is unclear whether patients in clinical practice receive treatment as recommended. We took advantage of population‐based registries in Norway to assess anti‐HER2 therapy patterns in real‐world data, with specific attention to the treatment of vulnerable groups. We included 715 patients with HER2+ mBC diagnosed from 2012 to 2021. Median age was 60 years, 473 (66%) had relapsed from early‐stage BC, and 440 (62%) had hormone receptor positive (HR+) disease. Anti‐HER2 therapy patterns aligned with national recommendations. Median treatment duration for first line therapy was 7.2 months, where 261 patients (55%) used trastuzumab and pertuzumab (±chemotherapy), followed by monotherapy with trastuzumab (195 patients, 41%). Second line therapy was initiated by 206 patients (43%), with a median duration of 7 months, where trastuzumab emtansine was the most prevalent therapy, used by 84 patients (41%). Third line therapy was initiated in 119 patients (25%) and 55 patients (11%) proceeded to fourth line therapy. The 182 patients (28%) who did not receive any anti‐HER2 therapy were older (74 years vs. 55 years) and had more comorbidity compared to treated patients. Among patients ≤75 years and healthy, 15% did not receive anti‐HER2 therapy. Patient characteristics strongly influence anti‐HER2 treatment patterns, and although numerous treatment options are available, a substantial proportion of HER2+ mBC patients did not receive targeted therapy. Undertreatment may be present.

• Moshina, Nataliia; Falk, Ragnhild Sørum; Botteri, Edoardo; Larsen, Marthe; Akslen, Lars Andreas & Ursin, Giske [Show all 8 contributors for this article] (2025). Long-term quality of life and quality adjusted life years after breast cancer: Impact of detection mode, tumor characteristics and treatment. Journal of Cancer Policy. 45. doi: 10.1016/j.jcpo.2025.100631. Full text in Research Archive
• Gjelsvik, Ylva Maria; Myklebust, Tor Åge; Fosså, Sophie Dorothea; Haug, Erik Skaaheim; Kvåle, Rune & Ursin, Giske [Show all 7 contributors for this article] (2025). A nationwide, longitudinal collection of patient-reported outcomes from prostate cancer patients and controls. Quality of Life Research. ISSN 0962-9343. 34, p. 2689–2700. doi: 10.1007/s11136-025-04017-7. Full text in Research Archive Show summary

  Purpose: Patient-reported outcomes (PROs) provide valuable information on adverse effects of cancer treatment. The aim of this study was to describe the feasibility of a population-based PROs collection and identify factors affecting participation. Methods: A total of 13 595 patients diagnosed with prostate cancer (PCa) 2017–2019, along with 10 653 age- and region-matched men with no history of PCa (controls), were invited to a health survey collecting PROs shortly after diagnosis and again one and three years after the initial invitation. Invitations were sent by digital or regular mail. The survey included Norwegian translations of the EQ-5D-5L, EORTC QLQ-C30, and EPIC-26 instruments. We assessed participation rates in all three survey rounds. Results: We invited 90% of newly diagnosed PCa patients to round 1 of the survey. Participation was higher among patients (58%) than controls (34%), with the highest response rate among digitally invited patients aged 60–69 (66%). Among patients, 44% participated in both rounds 1 and 2. Almost one third (32%) of the invited patients participated in all three rounds. Factors associated with higher participation included digital invitation, higher education, lower age, and being treated with curative intent. Among participants treated with curative intent, 51% completed the first questionnaire before starting local treatment. Conclusions: National registry-based PROs data collection is feasible for both PCa patients and controls. However, both non-responder and attrition biases are likely to influence questionnaire results. Institutions conducting population-based health surveys should provide information on non-responders and attrition to aid interpretation of questionnaire data.

• Kvåle, Rune; Ursin, Giske; Ekanger, Christian & Møller, Bjørn (2025). Considerable decline in prostate cancer mortality in Nordic countries after 2000. Acta Oncologica. ISSN 0284-186X. 64, p. 114–119. doi: 10.2340/1651-226X.2025.41334. Full text in Research Archive Show summary

  Background and purpose: In the late 1990s, the Nordic countries, with Norway at the top, were among the countries with the highest prostate cancer mortality in the world. We present updated mortality rates from the Nordic countries and discuss possible interpretations of changes in trends. Material and methods: Age-standardized rates for prostate-specific mortality in 1985–2022, estimated lifetime risk of death (0–84 years) and annual changes in mortality were obtained from the NORDCAN database. Joinpoint regression was used to evaluate trend changes for the period 1985–2022. For comparison, rates from other European countries from 2022 were retrieved from the GLOBOCAN database. Results: Between 1995–99 and 2018–22, mortality in men aged 40–84 years decreased from 38% in Denmark to 59% in Norway. By 2022 Norway had the second lowest mortality among the Nordic countries overall, and the lowest under 85 years. The life-time risk of dying from prostate cancer declined from 5.6–7.1% in 1995–99 to 3.1–4.2% in the last 5-year period. During the last years mortality has decreased most rapidly in Sweden (4.5% annually from 2016) and Norway (4.3% annually from 2014). The Nordic countries are no longer among the countries with the highest mortality in Europe. Interpretation: Mortality from prostate cancer has decreased significantly in the Nordic countries over the last decades. Possible explanatory factors are likely to include improvements in prostate cancer management strategies and treatment.

• Johansson, Anna L.V.; Skog, Anna; Johannessen, Tom Børge; Myklebust, Tor Åge; Kønig, Simon M. & Skovlund, Charlotte Wessel [Show all 19 contributors for this article] (2025). Changes in cancer incidence and stage during the COVID-19 pandemic in 2020–2021 in the Nordic countries. Acta Oncologica. ISSN 0284-186X. 64, p. 257–266. doi: 10.2340/1651-226X.2025.42079. Full text in Research Archive Show summary

  Background and purpose: The COVID-19 pandemic impacted substantially on cancer healthcare, including the temporary suspension of screening activities. We compared cancer incidence rates and stage during 2020–2021 to pre-pandemic rates in the Nordic countries. Material and methods: Using data from the national cancer registries in Denmark, Finland, Iceland, Norway, and Sweden, we estimated age-, sex-, and period-adjusted incidence rate ratios, expressed as relative percentage change (%) with 95% confidence intervals (CIs), comparing rates in 2020–2021 to those in 2017–2019 (pre-pandemic). Results: In 2020–2021, 340,675 cancer cases were diagnosed. The incidence rates declined during the first pandemic wave (Q2 2020), ranging from –21.7% [95% CI: –23.3%; –20.2%] (Sweden) to –7.9% [–17.7%; 3.0%] (Iceland). Incidence rates also declined in the second pandemic wave (Q1 2021), ranging from –8.6% [–10.2%; –6.9%] (Sweden) to –2.3% [–4.6%; 0.1%] (Norway), and in Sweden also by –3.1% [–4.8%; –1.3%] in the third pandemic wave (Q4 2021). Stage I breast cancer incidence declined during 2020 in Denmark/Norway/Sweden, with some catch-up in stage II incidence in 2021. Prostate cancer rates declined in Denmark/Finland/Norway/Sweden during 2020–2021, while melanoma rates declined in Finland in 2020. During 2020, colon cancer rates declined in Denmark and Iceland, while rectal cancer rates declined in Denmark, and lung and kidney cancer rates declined in Norway. Interpretation: During 2020–2021, cancer incidence rates declined across the Nordic countries with the largest declines in Sweden. During the third pandemic wave, the incidence rates were mostly similar to pre-pandemic rates. Changes in cancer stage may reflect reduced screening activities.

• Tsuruda, Kaitlyn; Langseth, Hilde; Ursin, Giske; Hofvind, Solveig Sand-Hanssen & Fortner, Shannon Renee Turzanski (2024). Validity of self-reported number of pregnancies and maternal age at first birth among females attending organized mammographic screening. Scandinavian Journal of Public Health. ISSN 1403-4948. doi: 10.1177/14034948241281197. Full text in Research Archive Show summary

  Aims: Reproductive history conveys information about potential health risks later in adulthood. This study aimed to examine the validity of self-reported number of pregnancies and maternal age at first birth (AFB) among females attending BreastScreen Norway.<p> <p>Methods: Participants were identified through the Janus Serum Bank cohort in Norway and were eligible for this cross-sectional validation study if they participated in a health survey issued by BreastScreen Norway between 2006 and 2015. Retrospective self-reported survey information on number of pregnancies and AFB in years was validated against prospectively collected information from the Medical Birth Registry of Norway (MBRN) using the Spearman rank (rs) and intraclass correlation coefficients (ICC) with 95% confidence intervals (CI).<p> <p>Results: After exclusions, 51,598 subjects were included in the analysis on number of pregnancies and 46,919 in the analysis on AFB. On average, study subjects were 59–60 years old when completing the health survey and had become first-time mothers roughly 36 years earlier. Survey-based information about number of pregnancies was highly correlated and demonstrated high agreement with the registry data (rs=0.967, 95% CI 0.964–0.969; ICC=0.884, 95% CI 0.882–0.885). Survey-based information about AFB demonstrated even higher correlation and very high agreement with the registry data (rs=0.975, 95% CI 0.973–0.976; ICC=0.974, 95% CI 0.974–0.975).<p> <p>Conclusions: Retrospectively recalled survey-based information about number of pregnancies and AFB was highly accurate when validated against prospectively collected information in the MBRN. These survey-based data are valuable for future epidemiological research, and linkage to the MBRN may not be required when these data are available.

• Ellingjord-Dale, Merete; Nygaard, Anders Benteson; Støer, Nathalie Charlotte; Bø, Ragnhild; Landrø, Nils Inge & Brunvoll, Sonja Hjellegjerde [Show all 14 contributors for this article] (2024). Temporal trajectories of long-COVID symptoms in adults with 22 months follow-up in a prospective cohort study in Norway. International Journal of Infectious Diseases. ISSN 1201-9712. 149, p. 1–8. doi: 10.1016/j.ijid.2024.107263. Full text in Research Archive Show summary

  Objectives There is a lack of large studies on long-COVID symptoms with symptoms measurements before the onset of COVID-19. Therefore, long-COVID is still poorly defined. Methods The Norwegian COVID-19 Cohort Study is a population-based, open cohort of adult participants (aged 18-96 years) from Norway. From March 27, 2020, participants were recruited through social media, invitations, and nationwide media coverage. Fourteen somatic and cognitive symptoms were assessed at baseline and four follow-ups for up to 22 months. SARS-CoV-2 test status was obtained from a mandatory national registry or from self-report. Results After follow-up, 15 737 participants had a SARS-CoV-2-positive test, 67 305 had a negative test, and 37 563 were still untested. Persistent symptoms reported more frequently by positive compared with negative participants one month after infection, were memory problems (3-6 months: adjusted odds ratio (aOR) = 6.8, CI = 5.7-8.1; >18 months: aOR = 9.4, CI = 4.1-22), and concentration problems (3-6 months: aOR = 4.1, CI = 3.5-4.7; >18 months: aOR = 4.4, CI = 2.0-9.7) as well fatigue, dyspnea, anosmia and dysgeusia. Conclusions COVID-19 was associated with cognitive symptoms, anosmia, dysgeusia, dyspnea, and fatigue as well as worsening of overall health up to 22 months after a SARS-CoV-2 test, even when correcting for symptoms before the onset of COVID-19.

• Svendsen, Karianne; Leithe, Sigrid; Trewin-Nybråten, Cassia Bree; Balto, Aina; Nes, Lise Solberg & Meland, Anders [Show all 12 contributors for this article] (2024). How Did Breast Cancer Patients Fare during Different Phases of the COVID-19 Pandemic in Norway Compared to Age-Matched Controls? Cancers. 16(3). doi: 10.3390/cancers16030602. Full text in Research Archive Show summary

  Little is known about how health-related quality of life (HRQoL) in breast cancer cases differed from that of controls during and after the COVID-19 pandemic. This study used data from an ongoing, nationwide HRQoL survey of 4279 newly diagnosed breast cancer cases and 2911 controls to investigate how breast cancer patients fared during different phases of the pandemic compared to controls. Responders during 2020–2022 were categorized into three COVID-19-related phases: the social restrictions phase, the high infection rate phase, and the post-pandemic phase. Across phases, breast cancer cases had significantly worse scores in most HRQoL domains compared to controls. Apart from slightly more insomnia in the high infection rate phase for both cases and controls, and better social functioning for young cases in the post-COVID-19 phase, the case-control differences in HRQoL remained consistent across phases. When the phases were assessed as one period, young women and those living with children

• Busund, Marit Katinka; Ursin, Giske; Lund, Tore Eiliv; Chen, Sairah Lai Fa & Rylander, Karin Charlotta Maria (2024). Menopausal hormone therapy and incidence, mortality, and survival of breast cancer subtypes: a prospective cohort study. Breast Cancer Research. ISSN 1465-5411. 26(1). doi: 10.1186/s13058-024-01897-4. Full text in Research Archive Show summary

  Background Menopausal hormone therapy (MHT) is associated with an increased risk of postmenopausal breast cancer, predominantly the luminal A-like subtype. The impact of MHT on deaths from breast cancer subtypes is less understood. This study aimed to explore associations between MHT use and the incidence, mortality, and survival of intrinsic-like breast cancer subtypes.<p> <p>Methods Data from 160,881 participants with self-reported MHT use from the prospective Norwegian Women and Cancer Study were analyzed. Among them, 7,844 incident breast cancer cases, and 721 breast cancer-specifc deaths occurred. Cox proportional hazard regression was performed to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the association between MHT use and the incidence, mortality, and survival of breast cancer subtypes. <p>Results MHT use was associated with increased risk of overall, luminal A-like, and luminal B-like breast cancer, with respective HRs of 1.44 (95% CI 1.36–1.52), 1.41 (95% CI 1.31–1.52), and 1.23 (95% CI 1.09–1.40) among current estrogen-progestin therapy (EPT) users compared with never users. The risk increased by 4%, 4%, and 2% per year of EPT use for overall, luminal A-like, and luminal B-like breast cancers, respectively. MHT use was also associated with increased risk of overall and luminal A-like breast cancer mortality, with HRs 1.61% (95% CI 1.36–1.91) and 2.15% (95% CI 1.51–3.05) increased risk among current EPT users compared with non-users. Among patients with breast cancer, pre-diagnostic MHT use was not associated with worse survival from overall breast cancer but was inversely associated with survival from triple-negative breast cancer (TNBC; HR death 0.41; 95% CI 0.24–0.73 among current users). Results varied significantly according to tumor subtype (pheterogeneity=0.02). <p>Conclusions Our study suggests that MHT use increases the risk of incident and fatal overall and luminal A-like, and incident luminal B-like breast cancer but does not decrease overall survival among patients with breast cancer. Further research is needed to elucidate the mechanisms underlying MHT use and breast cancer lethality, and to explore whether MHT use among patients with TNBC is indeed free from harm.

• Støer, Nathalie Charlotte; Vangen, Siri; Singh, Deependra; Fortner, Renee T.; Hofvind, Solveig & Ursin, Giske [Show all 7 contributors for this article] (2024). Menopausal hormone therapy and breast cancer risk: a population-based cohort study of 1.3 million women in Norway. British Journal of Cancer. ISSN 0007-0920. 131(1), p. 126–137. doi: 10.1038/s41416-024-02590-1. Full text in Research Archive Show summary

  <p>BACKGROUND: It is important to monitor the association between menopausal hormone therapy (HT) use and breast cancer (BC) risk with contemporary estimates, and specifically focus on HT types and new drugs. <p><p>METHODS: We estimated hazard ratios (HR) of BC risk according to HT type, administration route and individual drugs, overall and stratified by body mass index (BMI), molecular subtype and detection mode, with non-HT use as reference. <p>RESULTS: We included 1,275,783 women, 45+ years, followed from 2004, for a median of 12.7 years. Oral oestrogen combined with daily progestin was associated with the highest risk of BC (HR 2.42, 95% confidence interval (CI) 2.31–2.54), with drug-specific HRs ranging from Cliovelle®: 1.63 (95% CI 1.35–1.96) to Kliogest®: 2.67 (2.37–3.00). Vaginal oestradiol was not associated with BC risk. HT use was more strongly associated with luminal A cancer (HR 1.97, 95% CI 1.86–2.09) than other molecular subtypes, and more strongly with interval (HR 2.00, 95% CI: 1.83–2.30) than screen-detected (HR 1.33, 95% CI 1.26–1.41) BC in women 50–71 years. HRs for HT use decreased with increasing BMI. <p>CONCLUSIONS: The use of oral and transdermal HT was associated with an increased risk of BC. The associations varied according to HT type, individual drugs, molecular subtype, detection mode and BMI.

• Bøhn, Synne-Kristin Hoffart; Svendsen, Karianne; Balto, Aina; Gjelsvik, Ylva Maria; Myklebust, Tor Åge & Børøsund, Elin [Show all 13 contributors for this article] (2024). Health-related quality of life among women diagnosed with in situ or invasive breast cancer and age-matched controls: a population-based study. Journal of Patient-Reported Outcomes. 8(1). doi: 10.1186/s41687-024-00781-1. Full text in Research Archive Show summary

  Purpose: A breast cancer (BC) diagnosis may negatively affect health-related quality of life (HRQoL). However, there are few comparisons of HRQoL at several time points for women with BC, and particular when subdivided into invasive and in situ tumors. The purpose of this study was to investigate various aspects of HRQoL in women recently diagnosed with invasive BC or ductal carcinoma in situ (in situ) compared to age-matched BC free controls in a population-wide sample recruited through the Cancer Registry of Norway. Methods: This cross-sectional study utilized HRQoL data collected in 2020–2022 from a digital survey including 4117 cases (3867 women with invasive BC and 430 with in situ) and 2911 controls. HRQoL was assessed ≥ 21 days after diagnosis, using EORTC QLQ-C30. This includes scores assessing global quality of life (gHRQoL) and HRQoL functions and symptoms. Multivariable regression analyses were used to compare HRQoL between cases and controls and to identify factors associated with gHRQoL and fatigue. Additionally, HRQoL 14 months after diagnosis was analyzed in 1989 of the included cases and in 1212 of the controls. Score differences of ≥ 10 points were considered clinically relevant and thus presented in the results. Results: Invasive BC cases had lower gHRQoL, role- and social functioning in addition to more fatigue than controls. In situ cases had lower role—and social functioning than controls. Invasive BC cases scored worse than in situ on all domains, but the differences were not considered clinically relevant. Physical activity was associated with better gHRQoL and less fatigue in invasive BC, in situ and controls. Both invasive BC and in situ cases improved their role- and social functioning scores from diagnosis to 14 months follow-up, however no improvement was seen for fatigue. Conclusion: Women with invasive BC and in situ reported lower role- and social functioning scores than controls right after diagnosis with improvements 14 months after diagnosis. Physical activity was associated with better gHRQoL and less fatigue and should, whenever possible, play a key role in the care for BC patients.

• O'Driscoll, Jessica; Burton, Anya; Maskarinec, Gertraud; Perez-Gomez, Beatriz; Vachon, Celine & Miao, Hui [Show all 54 contributors for this article] (2024). Reproductive factors and mammographic density within the International Consortium of Mammographic Density: A cross-sectional study. Breast Cancer Research. ISSN 1465-5411. 26. doi: 10.1186/s13058-024-01890-x. Full text in Research Archive Show summary

  Background Elevated mammographic density (MD) for a woman’s age and body mass index (BMI) is an established breast cancer risk factor. The relationship of parity, age at first birth, and breastfeeding with MD is less clear. We examined the associations of these factors with MD within the International Consortium of Mammographic Density (ICMD). Methods ICMD is a consortium of 27 studies with pooled individual-level epidemiological and MD data from 11,755 women without breast cancer aged 35–85 years from 22 countries, capturing 40 country-& ethnicity-specific population groups. MD was measured using the area-based tool Cumulus. Meta-analyses across population groups and pooled analyses were used to examine linear regression associations of square-root (√) transformed MD measures (percent MD (PMD), dense area (DA), and non-dense area (NDA)) with parity, age at first birth, ever/never breastfed and lifetime breastfeeding duration. Models were adjusted for age at mammogram, age at menarche, BMI, menopausal status, use of hormone replacement therapy, calibration method, mammogram view and reader, and parity and age at first birth when not the association of interest. Results Among 10,988 women included in these analyses, 90.1% (n = 9,895) were parous, of whom 13% (n = 1,286) had ≥ five births. The mean age at first birth was 24.3 years (Standard deviation = 5.1). Increasing parity (per birth) was inversely associated with √PMD (β: − 0.05, 95% confidence interval (CI): − 0.07, − 0.03) and √DA (β: − 0.08, 95% CI: − 0.12, − 0.05) with this trend evident until at least nine births. Women who were older at first birth (per five-year increase) had higher √PMD (β:0.06, 95% CI:0.03, 0.10) and √DA (β:0.06, 95% CI:0.02, 0.10), and lower √NDA (β: − 0.06, 95% CI: − 0.11, − 0.01). In stratified analyses, this association was only evident in women who were post-menopausal at MD assessment. Among parous women, no associations were found between ever/never breastfed or lifetime breastfeeding duration (per six-month increase) and √MD. Conclusions Associations with higher parity and older age at first birth with √MD were consistent with the direction of their respective associations with breast cancer risk. Further research is needed to understand reproductive factor-related differences in the composition of breast tissue and their associations with breast cancer risk.

• Sarkeala, Tytti; Lamminmäki, Maarit; Nygård, Mari; Njor, Sisse Helle; Virtanen, Anni & Leivonen, Aku [Show all 12 contributors for this article] (2023). Cervical, liver and stomach cancer incidence and mortality in non-Western immigrant women: a retrospective cohort study from four Nordic countries. Acta Oncologica. ISSN 0284-186X. 62(9), p. 977–987. doi: 10.1080/0284186X.2023.2245557. Full text in Research Archive Show summary

  Background Cervical, liver and stomach cancers are the most common infection-associated malignancies and the leading cause of morbidity in non-Western regions. We compared the incidence and mortality of these cancers between non-Western immigrant and non-immigrant Nordic female populations. We also analysed the effect of age at immigration, duration of residence and education on cancer burden. Material and Methods Study population consisted of women residents in Denmark, Finland, Iceland and Norway in 1973–2020. Non-Western women contributed 3.1% of the total 260 million person-years at risk. All women were followed from their 20th birthday, or from the date of immigration if after, until the date of their first primary cancer diagnosis, death, emigration, or the end of the country-specific study period. All data were adjusted for 10-year age groups and calendar periods, and immigrant data was further broken down by region of birth, age at immigration and education level. Country-specific estimates were produced by multivariable Poisson regression and pooled in Finland with a random effects model. Results Altogether, there were 60 982 cases of cervical, liver and stomach cancer in the study population, causing 36 582 deaths. The immigrant women had significantly higher liver (rate ratio [RR] 1.78, 95% confidence interval (CI) 1.03–3.06) and stomach cancer incidence (RR 1.68, CI 1.29–2.18), and stomach cancer mortality (RR 1.49, CI 1.17–1.92) than non-immigrant women. In the immigrant population, high education was related to lower incidence and mortality of studied cancers. The rate ratio of cervical cancer decreased with duration of residence and increased with rising age at immigration. Conclusion Due to the increased incidence and mortality of infection-related cancers and changes in cancer patterns by age at immigration and duration of residence, attention should be paid to targeted health care services for immigrants. Special efforts should be given to women who have spent their youth in high-risk areas.

• Johansson, Anna; Skog, Anna; Johannessen, Tom Børge; Myklebust, Tor Åge; Skovlund, Charlotte Wessel & Mørch, Lina Steinrud [Show all 17 contributors for this article] (2023). Were cancer patients worse off than the general population during the COVID-19 pandemic? A population-based study from Norway, Denmark and Iceland during the pre-vaccination era. The Lancet Regional Health - Europe. 31, p. 1–11. doi: 10.1016/j.lanepe.2023.100680. Full text in Research Archive Show summary

  Background In a population-based setting, we investigated the risks of testing positive for SARS-CoV-2 and developing severe COVID-19 outcomes among cancer patients compared with the general population. Methods In nationwide cohorts, we identified all individuals in Norway, Denmark and Iceland who tested positive for SARS-CoV-2 or had a severe COVID-19 outcome (hospitalisation, intensive care, and death) from March until December 2020, using data from national health registries. We estimated standardised incidence ratios (SIRs) with 95% confidence intervals (CIs) comparing cancer patients with the general population. Findings During the first wave of the pandemic, cancer patients in Norway and Denmark had higher risks of testing SARS-CoV-2 positive compared to the general population. Throughout 2020, recently treated cancer patients were more likely to test SARS-CoV-2 positive. In Iceland, cancer patients experienced no increased risk of testing positive. The risk of COVID-19-related hospitalisation was higher among cancer patients diagnosed within one year of hospitalisation (Norway: SIR = 2.43, 95% CI 1.89–3.09; Denmark: 2.23, 1.96–2.54) and within five years (Norway: 1.58, 1.35–1.83; Denmark: 1.54, 1.42–1.66). Risks were higher in recently treated cancer patients and in those diagnosed with haematologic malignancies, colorectal or lung cancer. Risks of COVID-19-related intensive care and death were higher among cancer patients. Interpretation Cancer patients were at increased risk of testing positive for SARS-CoV-2 during the first pandemic wave when testing availability was limited, while relative risks of severe COVID-19 outcomes remained increased in cancer patients throughout 2020. Recent cancer treatment and haematologic malignancy were the strongest risk factors.

• Bentzen, Heidi Beate; Olav, Hilde Kvammen & Ursin, Giske (2023). Maximizing the GDPR potential for data transfers: first in Europe. The Lancet Regional Health - Europe. 27. doi: 10.1016/j.lanepe.2023.100600. Full text in Research Archive Show summary

  During the pandemic, rapid international data sharing was key to finding medical solutions. Legal derogations made some pandemic data transfers possible.1 However, non-pandemic medical research, including cancer research, follows regular legal rules, and these rules currently create data transfer stalls, delaying medical advancements.1 Data transfers from the European Union (EU) to federal institutions in the United Stated (US) for medical research are currently impeded for legal reasons.2, 3, 4 Transfers to most of the US private sector can proceed provided appropriate safeguards are in place, but presently, US cloud providers such as Amazon Web Services, Google Cloud, and Microsoft Azure that provide large-scale, advanced data processing solutions can often not be used.5 Legal challenges therefore affect clinical trials when 1) the pharmaceutical company uses a US subcontractor providing a cloud-based analysis platform, and/or 2) legally mandated information including safety data must be reported to regulatory authorities such as the US Food and Drug Administration (FDA). In the following, we describe the use of a very narrow safety valve derogation in the EU General Data Protection Regulation (GDPR) 2016/679 to enable such transfers. The Norwegian Data Protection Authority (DPA) concurred with our use of this legal option. To our knowledge, this is the first time-use of this derogation in Europe.

• Wu, Zeni; Trabert, Britton; Guillemette, Chantal; Caron, Patrick; Bradwin, Gary & Graubard, Barry I. [Show all 10 contributors for this article] (2023). Prediagnostic Hormone Levels and Risk of Testicular Germ Cell Tumors: A Nested Case–Control Study in the Janus Serum Bank. Cancer Epidemiology, Biomarkers and Prevention. ISSN 1055-9965. 32(11), p. 1564–1571. doi: 10.1158/1055-9965.EPI-23-0772. Full text in Research Archive
• Visvanathan, Kala; Mondul, Alison M.; Zeleniuch-Jacquotte, Anne; Wang, Molin; Gail, Mitchell H. & Yaun, Shiaw-Shyuan [Show all 58 contributors for this article] (2023). Circulating vitamin D and breast cancer risk: an international pooling project of 17 cohorts. European Journal of Epidemiology (EJE). ISSN 0393-2990. 38(1), p. 11–29. doi: 10.1007/s10654-022-00921-1. Full text in Research Archive Show summary

  Laboratory and animal research support a protective role for vitamin D in breast carcinogenesis, but epidemiologic studies have been inconclusive. To examine comprehensively the relationship of circulating 25-hydroxyvitamin D [25(OH)D] to subsequent breast cancer incidence, we harmonized and pooled participant-level data from 10 U.S. and 7 European prospective cohorts. Included were 10,484 invasive breast cancer cases and 12,953 matched controls. Median age (interdecile range) was 57 (42–68) years at blood collection and 63 (49–75) years at breast cancer diagnosis. Prediagnostic circulating 25(OH)D was either newly measured using a widely accepted immunoassay and laboratory or, if previously measured by the cohort, calibrated to this assay to permit using a common metric. Study-specific relative risks (RRs) for season-standardized 25(OH)D concentrations were estimated by conditional logistic regression and combined by random-effects models. Circulating 25(OH)D increased from a median of 22.6 nmol/L in consortium-wide decile 1 to 93.2 nmol/L in decile 10. Breast cancer risk in each decile was not statistically significantly different from risk in decile 5 in models adjusted for breast cancer risk factors, and no trend was apparent (P-trend = 0.64). Compared to women with sufficient 25(OH)D based on Institute of Medicine guidelines (50– < 62.5 nmol/L), RRs were not statistically significantly different at either low concentrations (< 20 nmol/L, 3% of controls) or high concentrations (100– < 125 nmol/L, 3% of controls; ≥ 125 nmol/L, 0.7% of controls). RR per 25 nmol/L increase in 25(OH)D was 0.99 [95% confidence intervaI (CI) 0.95–1.03]. Associations remained null across subgroups, including those defined by body mass index, physical activity, latitude, and season of blood collection. Although none of the associations by tumor characteristics reached statistical significance, suggestive inverse associations were seen for distant and triple negative tumors. Circulating 25(OH)D, comparably measured in 17 international cohorts and season-standardized, was not related to subsequent incidence of invasive breast cancer over a broad range in vitamin D status.

• Lamminmäki, Maarit; Leivonen, Aku; Heinävaara, Sirpa; Nygård, Mari; Ursin, Giske & Campbell, Suzanne [Show all 12 contributors for this article] (2023). A population-based cohort study on changes in breast, lung and colorectal cancer incidence and mortality among non-Western immigrant women. BMC Cancer. 23(1). doi: 10.1186/s12885-023-11140-6. Full text in Research Archive Show summary

  Background Cancer risk varies geographically, and migrants are influenced by different risk factors before, during and after migration. Increased migration from non-Western countries to the Nordic countries calls for a better understanding of the migrants’ cancer risk and the change in risk patterns over time. The aim of this study was to compare the incidence and mortality of breast, colorectal and lung cancer between non-Western immigrant and the native female population in Denmark, Finland, Iceland, and Norway. Material and methods Data from national registries were processed and pre-analysed in each country. Multivariate Poisson regression models were used to model the relative differences in incidence and mortality as rate ratios (RR). The country-specific estimates and summary statistics were pooled together using a random effects model. Results Non-Western immigrant women had significantly lower breast (RR 0.71, 0.65–0.78), colorectal (RR 0.72, 0.57–0.92) and lung (RR 0.55, 0.42–0.72) cancer incidence rates than native women, and the risk of these cancers among immigrant women increased with duration of residence. Differences were parallel in breast, colorectal and lung cancer mortality (RR 0.64, 0.55–0.74; RR 0.66, 0.48–0.92; RR 0.51, 0.34–0.79). Among immigrant women, higher education increased the risk for breast cancer and decreased it for lung cancer. Conclusion The results significantly complement and add to the previous findings of cancer burden and cancer burden transition among migrants and provide evidence of a prolonged cancer risk advantage among non-Western immigrant women. However, the findings show an increasing risk of lifestyle-related cancers with increasing duration of residence in the host country. Further studies are needed to discover underlying reasons for this phenomenon.

• Børøsund, Elin; Meland, Anders; Eriksen, Hege Randi; Rygg, Christine Marie; Ursin, Giske & Nes, Lise Solberg (2023). Digital Cognitive Behavioral- and Mindfulness-Based Stress-Management Interventions for Survivors of Breast Cancer: Development Study. JMIR Formative Research. 7(1), p. 1–12. doi: 10.2196/48719. Full text in Research Archive Show summary

  Background: Psychosocial stress-management interventions can reduce stress and distress and improve the quality of life for survivors of cancer. As these in-person interventions are not always offered or accessible, evidence-informed digital stress-management interventions may have the potential to improve outreach of psychosocial support for survivors of cancer. Few such digital interventions exist so far, few if any have been developed specifically for survivors of breast cancer, and few if any have attempted to explore more than 1 distinct type of intervention framework. Objective: This study aimed to develop 2 digital psychosocial stress-management interventions for survivors of breast cancer; 1 cognitive behavioral therapy-based intervention (CBI), and 1 mindfulness-based intervention (MBI). Methods: The development of the CBI and MBI interventions originated from the existing StressProffen program, a digital stress-management intervention program for survivors of cancer, based on a primarily cognitive behavioral therapeutic concept. Development processes entailed a multidisciplinary design approach and were iteratively conducted in close collaboration between key stakeholders, including experts within psychosocial oncology, cancer epidemiology, stress-management, and eHealth as well as survivors of breast cancer and health care providers. Core psychosocial oncology stress-management and cancer epidemiology experts first conducted a series of workshops to identify cognitive behavioral and mindfulness specific StressProffen content, overlapping psychoeducational content, and areas where development and incorporation of new material were needed. Following the program content adaptation and development phase, phases related to user testing of new content and technical, privacy, security, and ethical aspects and adjustments ensued. Intervention content for the distinct CBI and MBI interventions was refined in iterative user-centered design processes and adjusted to electronic format through stakeholder-centered iterations. Results: For the CBI version, the mindfulness-based content of the original StressProffen was removed, and for the MBI version, cognitive behavioral content was removed. Varying degrees of new content were created for both versions, using a similar layout as for the original StressProffen program. New content and new exercises in particular were tested by survivors of breast cancer

• Kjaer, Trille Kristina; Andersen, Elisabeth Anne Wreford; Ursin, Giske; Larsen, Signe Benzon; Bidstrup, Pernille Envold & Winther, Jeanette Falck [Show all 9 contributors for this article] (2023). Cumulative incidence of second primary cancers in a large nationwide cohort of Danish cancer survivors: a population-based retrospective cohort study. The Lancet Oncology. ISSN 1470-2045. 25(1), p. 126–136. doi: 10.1016/S1470-2045(23)00538-7. Full text in Research Archive
• Löfling, Leif Lukas; Støer, Nathalie Charlotte; Nafisi, Sara; Ursin, Giske; Hofvind, Solveig Sand-Hanssen & Botteri, Edoardo (2023). Low-dose aspirin and risk of breast cancer: a Norwegian population-based cohort study of one million women. European Journal of Epidemiology (EJE). ISSN 0393-2990. 38, p. 413–426. doi: 10.1007/s10654-023-00976-8. Full text in Research Archive Show summary

  Several studies evaluated the association between aspirin use and risk of breast cancer (BC), with inconsistent results. We identifed women aged≥50 years residing in Norway between 2004 and 2018, and linked data from nationwide registries; including the Cancer Registry of Norway, the Norwegian Prescription Database, and national health surveys. We used Cox regression models to estimate the association between low-dose aspirin use and BC risk, overall and by BC characteristics, women’s age and body mass index (BMI), adjusting for sociodemographic factors and use of other medications. We included 1,083,629 women. During a median follow-up of 11.6 years, 257,442 (24%) women used aspirin, and 29,533 (3%) BCs occurred. For current use of aspirin, compared to never use, we found an indication of a reduced risk of oestrogen receptorpositive (ER+) BC (hazard ratio [HR]=0.96, 95% confdence interval [CI]: 0.92–1.00), but not ER-negative BC (HR=1.01, 95%CI: 0.90–1.13). The association with ER+BC was only found in women aged≥65 years (HR=0.95, 95%CI: 0.90–0.99), and became stronger as the duration of use increased (use of≥4 years HR=0.91, 95%CI: 0.85–0.98). BMI was available for 450,080 (42%) women. Current use of aspirin was associated with a reduced risk of ER+BC in women with BMI≥25 (HR=0.91, 95%CI: 0.83–0.99; HR=0.86, 95%CI: 0.75–0.97 for use of≥4 years), but not in women with BMI<25.Use of low-dose aspirin was associated with reduced risk of ER+BC, in particular in women aged≥65 years and overweight women.

• Löfling, Lukas; Støer, Nathalie Charlotte; Kulle, Bettina; Ursin, Giske & Botteri, Edoardo (2023). Low-dose aspirin, statins, and metformin and survival in patients with breast cancers: a Norwegian population-based cohort study. Breast Cancer Research. ISSN 1465-5411. 25, p. 1–11. doi: 10.1186/s13058-023-01697-2. Full text in Research Archive Show summary

  Background Previous studies assessed the prognostic effect of aspirin, statins, and metformin in breast cancer (BC) patients, with inconclusive results. Methods We performed a nationwide population-based cohort study to evaluate if post-diagnostic use of low-dose aspirin, statins, and metformin was associated with BC-specific survival. Women aged ≥ 50 years and diagnosed with BC in 2004–2017, who survived ≥ 12 months after diagnosis (follow-up started 12 months after diagnosis), were identified in the Cancer Registry of Norway. The Norwegian Prescription Database provided information on prescriptions. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between post-diagnostic use and BC-specific survival, overall and by oestrogen receptor (ER) status. Results A total of 26,190 patients were included. Of these, 5324 (20%), 7591 (29%), and 1495 (6%) were post-diagnostic users of low-dose aspirin, statins, and metformin, respectively. The median follow-up was 6.1 years, and 2169 (8%) patients died from BC. HRs for use, compared to no use, were estimated at 0.96 (95% CI 0.85–1.08) for low-dose aspirin (ER+: HR = 0.97, 95% CI 0.83–1.13; ER−: HR = 0.97, 95% CI 0.73–1.29, p value for interaction = 0.562), 0.84 (95% CI 0.75–0.94) for statins (ER+: HR = 0.95, 95% CI 0.82–1.09; ER−: HR = 0.77, 95% CI 0.60–1.00, p value for interaction = 0.259), and 0.70 (95% CI 0.51–0.96) for metformin (compared to use of non-metformin antidiabetics) (ER+: HR = 0.67, 95% CI 0.45–1.01; ER−: HR = 1.62, 95% CI 0.72–3.62, p value for interaction = 0.077). Conclusion We found evidence supporting an association between post-diagnostic use of statins and metformin and survival, in patients with BC. Our findings indicate potential differences according to ER status.

• Busund, Marit Katinka; Ursin, Giske; Lund, Eiliv; Wilsgaard, Tom & Rylander, Karin Charlotta Maria (2023). Trajectories of body mass index in adulthood and risk of subtypes of postmenopausal breast cancer. Breast Cancer Research. ISSN 1465-5411. 25(1). doi: 10.1186/s13058-023-01729-x. Full text in Research Archive Show summary

  Background - Body fatness is a dynamic exposure throughout life. To provide more insight into the association between body mass index (BMI) and postmenopausal breast cancer, we aimed to examine the age at onset, duration, intensity, and trajectories of body fatness in adulthood in relation to risk of breast cancer subtypes.<p> <p>Methods - Based on self-reported anthropometry in the prospective Norwegian Women and Cancer Study, we calculated the age at onset, duration, and intensity of overweight and obesity using linear mixed-effects models. BMI trajectories in adulthood were modeled using group-based trajectory modeling. We used Cox proportional hazards models to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for the associations between BMI exposures and breast cancer subtypes in 148,866 postmenopausal women.<p> <p>Results - A total of 7223 incident invasive postmenopausal breast cancer cases occurred during follow-up. Increased overweight duration and age at the onset of overweight or obesity were associated with luminal A-like breast cancer. Significant heterogeneity was observed in the association between age at overweight and overweight duration and the intrinsic-like subtypes (pheterogeneity 0.03). Compared with women who remained at normal weight throughout adulthood, women with a descending BMI trajectory had a reduced risk of luminal A-like breast cancer (HR 0.54, 95% CI 0.33–0.90), whereas women with ascending BMI trajectories were at increased risk (HR 1.09; 95% CI 1.01–1.17 for “Normal-overweight”; HR 1.20; 95% CI 1.07–1.33 for “Normal-obesity”). Overweight duration and weighted cumulative years of overweight and obesity were inversely associated with luminal B-like breast cancer.<p> <p>Conclusions - In this exploratory analysis, decreasing body fatness from obesity in adulthood was inversely associated with overall, hormone receptor-positive and luminal A-like breast cancer in postmenopausal women. This study highlights the potential health benefits of reducing weight in adulthood and the health risks associated with increasing weight throughout adult life. Moreover, our data provide evidence of intrinsic-like tumor heterogeneity with regard to age at onset and duration of overweight.

• Ward, Sarah V.; Burton, Anya; Tamimi, Rulla M.; Pereira, Ana; Garmendia, Maria Luisa & Pollan, Marina [Show all 52 contributors for this article] (2022). The association of age at menarche and adult height with mammographic density in the International Consortium of Mammographic Density. Breast Cancer Research. ISSN 1465-5411. 24(49). doi: 10.1186/s13058-022-01545-9. Full text in Research Archive Show summary

  Background Early age at menarche and tall stature are associated with increased breast cancer risk. We examined whether these associations were also positively associated with mammographic density, a strong marker of breast cancer risk. Methods Participants were 10,681 breast-cancer-free women from 22 countries in the International Consortium of Mammographic Density, each with centrally assessed mammographic density and a common set of epidemiologic data. Study periods for the 27 studies ranged from 1987 to 2014. Multi-level linear regression models estimated changes in square-root per cent density (√PD) and dense area (√DA) associated with age at menarche and adult height in pooled analyses and population-specific meta-analyses. Models were adjusted for age at mammogram, body mass index, menopausal status, hormone therapy use, mammography view and type, mammographic density assessor, parity and height/age at menarche. Results In pooled analyses, later age at menarche was associated with higher per cent density (β√PD = 0.023 SE = 0.008, P = 0.003) and larger dense area (β√DA = 0.032 SE = 0.010, P = 0.002). Taller women had larger dense area (β√DA = 0.069 SE = 0.028, P = 0.012) and higher per cent density (β√PD = 0.044, SE = 0.023, P = 0.054), although the observed effect on per cent density depended upon the adjustment used for body size. Similar overall effect estimates were observed in meta-analyses across population groups. Conclusions In one of the largest international studies to date, later age at menarche was positively associated with mammographic density. This is in contrast to its association with breast cancer risk, providing little evidence of mediation. Increased height was also positively associated with mammographic density, particularly dense area. These results suggest a complex relationship between growth and development, mammographic density and breast cancer risk. Future studies should evaluate the potential mediation of the breast cancer effects of taller stature through absolute breast density.

• Ellingjord-Dale, Merete; Kalleberg, Karl Trygve; Istre, Mette Stausland; Nygaard, Anders Benteson; Brunvoll, Sonja Hjellegjerde & Eggesbø, Linn Margrethe [Show all 10 contributors for this article] (2022). The use of public transport and contraction of SARS-CoV-2 in a large prospective cohort in Norway. BMC Infectious Diseases. 22(1). doi: 10.1186/s12879-022-07233-5. Full text in Research Archive Show summary

  Background For many people public transport is the only mode of travel, and it can be challenging to keep the necessary distances in such a restricted space. The exact role of public transportation and risk of SARS-CoV-2 transmission is not known. Methods Participants (n = 121,374) were untested adult Norwegian residents recruited through social media who in the spring of 2020 completed a baseline questionnaire on demographics and the use of public transport. Incident cases (n = 1069) had a positive SARS-CoV-2 polymerase chain reaction test registered at the Norwegian Messaging System for Infectious Diseases by January 27, 2021. We investigated the association between the use of public transport and SARS-CoV-2 using logistic regression. Odds ratios (ORs) with 95% confidence intervals (CIs) adjusted for age, calendar time, gender, municipality, smoking, income level, fitness and underlying medical conditions were estimated. Frequency of the use of public transport was reported for 2 week-periods. Results Before lockdown, those who tested positive on SARS-CoV-2 were more likely to have used public transport 1–3 times (OR = 1.28, CI 1.09–1.51), 4–10 times (OR = 1.49, CI 1.26–1.77) and ≥ 11 times (OR = 1.50, CI 1.27–1.78, p for trend < 0.0001) than those who had not tested positive. Conclusion The use of public transport was positively associated with contracting SARS-CoV-2 both before and after lockdown.

• Botteri, Edoardo; Hoff, Geir; Randel, Kristin Ranheim; Holme, Øyvind; Lange, Thomas de & Bernklev, Tomm [Show all 16 contributors for this article] (2022). Characteristics of nonparticipants in a randomised colorectal cancer screening trial comparing sigmoidoscopy and faecal immunochemical testing. International Journal of Cancer. ISSN 0020-7136. 151(3), p. 361–371. doi: 10.1002/ijc.34025. Full text in Research Archive Show summary

  Public health systems should guarantee universal access to health care services, including cancer screening. We assessed whether certain population subgroups were underrepresented among participants in colorectal cancer screening with sigmoidoscopy and faecal immunochemical testing (FIT). Between 2012 and 2019, about 140 000 individuals aged 50 to 74 years were randomly invited to once-only sigmoidoscopy or first round of FIT screening. Our study included 46 919 individuals invited to sigmoidoscopy and 70 019 to FIT between 2012 and 2017. We used logistic regression models to evaluate if demographic and socioeconomic factors and use of certain drugs were associated with participation. Twenty-four thousand one hundred and fifty-nine (51.5%) individuals attended sigmoidoscopy and 40 931 (58.5%) FIT screening. Male gender, young age, low education and income, being retired or unemployed, living alone, being an immigrant, long driving time to screening centre, and use of antidiabetic and psychotropic drugs were associated with low participation in both screening groups. Many of these factors also predicted low acceptance of colonoscopy after positive FIT. While male gender, young age and living alone were more strongly associated with nonparticipation in FIT than sigmoidoscopy, low education and income, being retired or immigrant and long driving time were more strongly associated with nonparticipation in sigmoidoscopy than FIT. In conclusion, participation was lower in sigmoidoscopy than FIT. Predictors of nonparticipation were similar between arms. However, low socioeconomic status, being an immigrant and long driving time affected participation more in sigmoidoscopy screening, suggesting that FIT may guarantee more equal access to screening services than sigmoidoscopy.

• Johansson, Anna L. V.; Larønningen, Siri; Skovlund, Charlotte Wessel; Kristiansen, Marnar Fríðheim; Mørch, Lina Steinrud & Friis, Søren [Show all 18 contributors for this article] (2022). The impact of the COVID-19 pandemic on cancer diagnosis based on pathology notifications: A comparison across the Nordic countries during 2020. International Journal of Cancer. ISSN 0020-7136. 151(3), p. 381–395. doi: 10.1002/ijc.34029. Full text in Research Archive Show summary

  The severity of the COVID-19 pandemic and subsequent mitigation strategies have varied across the Nordic countries. In a joint Nordic population-based effort, we compared patterns of new cancer cases and notifications between the Nordic countries during 2020. We used pathology notifications to cancer registries in Denmark, the Faroe Islands, Finland, Iceland, Norway and Sweden to determine monthly numbers of pathology notifications of malignant and in situ tumours from January to December 2020 compared to 2019 (2017-2019 for Iceland and the Faroe Islands). We compared new cancer cases per month based on unique individuals with pathology notifications. In April and May 2020, the numbers of new malignant cases declined in all Nordic countries, except the Faroe Islands, compared to previous year(s). The largest reduction was observed in Sweden (May: −31.2%, 95% CI −33.9, −28.3), followed by significant declines in Finland, Denmark and Norway, and a nonsignificant decline in Iceland. In Denmark, Norway, Sweden and Finland the reporting rates during the second half of 2020 rose to almost the same level as in 2019. However, in Sweden and Finland, the increase did not compensate for the spring decline (annual reduction −6.2% and −3.6%, respectively). Overall, similar patterns were observed for in situ tumours. The COVID-19 pandemic led to a decline in rates of new cancer cases in Sweden, Finland, Denmark and Norway, with the most pronounced reduction in Sweden. Possible explanations include the severity of the pandemic, temporary halting of screening activities and changes in healthcare seeking behaviour. What's new? The severity of the COVID-19 pandemic and subsequent mitigation strategies have varied across the Nordic countries. This is the first international comparison of cancer notification rates during the first year of the COVID-19 pandemic, including six countries with similar tax-funded healthcare systems and population-based cancer reporting. The findings suggest that, despite differences in pandemic mitigation efforts, the severity of the pandemic may have had a larger effect on cancer detection than strict societal restrictions. In all countries, it will be of importance to monitor future trends in late-stage cancer incidence and survival.

• Löfling, Lukas; Støer, Nathalie Charlotte; Sloan, Erica K.; Chang, Aeson; Gandini, Sara & Ursin, Giske [Show all 7 contributors for this article] (2022). β-blockers and breast cancer survival by molecular subtypes: a population-based cohort study and meta-analysis. British Journal of Cancer. ISSN 0007-0920. 127, p. 1086–1096. doi: 10.1038/s41416-022-01891-7. Full text in Research Archive Show summary

  Abstract Background The association between use of β-blockers and breast cancer (BC) prognosis has been investigated in several observational studies, with conflicting results. We performed a nationwide cohort study and a meta-analysis to investigate the association, and assess if it varied between molecular subtypes of BC. Methods We identified women aged ≥50 years with BC diagnosed between 2004 and 2018 in Norway. We used Cox regression models to estimate the association between β-blocker use at diagnosis and BC-specific survival, overall and by molecular subtype. We performed a meta-analysis of observational studies that reported molecular subtype-specific estimates of this association. Results We included 30,060 women, of which 4461 (15%) used β-blockers. After a median follow-up of 5.1 years, 2826 (9%) died of BC. Overall, β-blocker use was not associated with BC-specific survival (hazard ratio [HR] = 1.07; 95% confidence interval [CI]: 0.97–1.19). We found an association only in triple-negative BC (TNBC) patients (HR = 0.66; 95% CI: 0.47–0.91). This was confirmed in the meta-analysis: β-blocker use was associated with progression/recurrence-free (HR = 0.58; 95% CI: 0.38–0.89) and BC-specific survival (HR = 0.74; 95% CI: 0.55–1.00) in TNBC patients only. Conclusion In our cohort of BC patients and in the meta-analysis, β-blocker use was associated with prolonged BC-specific survival only in TNBC patients.

• Townsend, Mary K.; Trabert, Britton; Fortner, Renée T.; Arslan, Alan A.; Buring, Julie E. & Carter, Brian D. [Show all 42 contributors for this article] (2022). Cohort Profile: The Ovarian Cancer Cohort Consortium (OC3). International Journal of Epidemiology. ISSN 0300-5771. 51(3), p. E73–E86. doi: 10.1093/ije/dyab211. Full text in Research Archive
• Larsen, Marthe; Aglen, Camilla Flåt; Lee, Christoph I.; Hoff, Solveig Roth; Lund-Hanssen, Håkon & Lång, Kristina [Show all 9 contributors for this article] (2022). Artificial Intelligence Evaluation of 122969 Mammography Examinations from a Population-based Screening Program. Radiology. ISSN 0033-8419. 303(3), p. 502–511. doi: 10.1148/radiol.212381. Full text in Research Archive Show summary

  The performance of the artificial intelligence system was promising for breast cancer detection in a large population-based mammography screening program. Background Artificial intelligence (AI) has shown promising results for cancer detection with mammographic screening. However, evidence related to the use of AI in real screening settings remain sparse. Purpose To compare the performance of a commercially available AI system with routine, independent double reading with consensus as performed in a population-based screening program. Furthermore, the histopathologic characteristics of tumors with different AI scores were explored. Materials and Methods In this retrospective study, 122 969 screening examinations from 47 877 women performed at four screening units in BreastScreen Norway from October 2009 to December 2018 were included. The data set included 752 screen-detected cancers (6.1 per 1000 examinations) and 205 interval cancers (1.7 per 1000 examinations). Each examination had an AI score between 1 and 10, where 1 indicated low risk of breast cancer and 10 indicated high risk. Threshold 1, threshold 2, and threshold 3 were used to assess the performance of the AI system as a binary decision tool (selected vs not selected). Threshold 1 was set at an AI score of 10, threshold 2 was set to yield a selection rate similar to the consensus rate (8.8%), and threshold 3 was set to yield a selection rate similar to an average individual radiologist (5.8%). Descriptive statistics were used to summarize screening outcomes. Results A total of 653 of 752 screen-detected cancers (86.8%) and 92 of 205 interval cancers (44.9%) were given a score of 10 by the AI system (threshold 1). Using threshold 3, 80.1% of the screen-detected cancers (602 of 752) and 30.7% of the interval cancers (63 of 205) were selected. Screen-detected cancer with AI scores not selected using the thresholds had favorable histopathologic characteristics compared to those selected; opposite results were observed for interval cancer. Conclusion The proportion of screen-detected cancers not selected by the artificial intelligence (AI) system at the three evaluated thresholds was less than 20%. The overall performance of the AI system was promising according to cancer detection.

• Simon, Julia; Brenner, Nicole; Reich, Sibylle; Langseth, Hilde; Hansen, Bo Lars Thorvald Terning & Ursin, Giske [Show all 13 contributors for this article] (2022). Nasopharyngeal carcinoma patients from Norway show elevated Epstein-Barr virus IgA and IgG antibodies prior to diagnosis. Cancer Epidemiology. ISSN 1877-7821. 77. doi: 10.1016/j.canep.2022.102117. Full text in Research Archive
• Gjelsvik, Ylva Maria; Johannessen, Tom Børge; Ursin, Giske & Myklebust, Tor Åge (2022). A nationwide, prospective collection of patient reported outcomes in the Cancer Registry of Norway. Norsk Epidemiologi. ISSN 0803-2491. 30(1-2), p. 47–53. doi: 10.5324/nje.v30i1-2.4977. Full text in Research Archive
• Vik, Kirsti Lund; Johansson, Anna L. V.; Trewin, Cassia Bree; Russnes, Hege Elisabeth Giercksky & Ursin, Giske (2022). Incidence of breast cancer subtypes in immigrant and non-immigrant women in Norway. Breast Cancer Research. ISSN 1465-5411. 24(4). doi: 10.1186/s13058-021-01498-5. Full text in Research Archive Show summary

  Background Breast cancer incidence differs between non-immigrants and immigrants from low- and middle-income countries. This study investigates whether immigrants also have different subtype-specific incidences. Methods We used national health registries in Norway and calculated subtype-specific incidence rate ratios (IRRs) for invasive breast cancer among women aged 20–75 and 20–49 years between 2005 and 2015. Immigrant groups were classified by country of birth broadly defined based on WHO regional groupings. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A-like (ER+ PR+ HER2-), luminal B-like/HER2- (ER+ PR- HER2-), luminal B-like/HER2+ (ER+ PR any HER2+), HER2+ (ER-PR-HER2+) and triple-negative breast cancer (TNBC) (ER-PR-HER2-). Results Compared to non-immigrants, incidence of the luminal A-like subtype was lower in immigrants from Sub-Saharan Africa (IRR 0.43 95% CI 0.28–0.66), South East Asia (IRR 0.63 95% CI 0.51–0.79), South Asia (IRR 0.67 95% CI 0.52–0.86) and Eastern Europe (IRR 0.86 95% CI 0.76–0.99). Immigrants from South Asia had higher rates of HER2 + tumors (IRR 2.02 95% CI 1.26–3.23). The rates of TNBC tended to be similar regardless of region of birth, except that women from South East Asia had an IRR of 0.54 (95% CI 0.32–0.91). Conclusions Women from Eastern Europe, Sub-Saharan Africa and Asia had different subtype-specific incidences compared to women from high-income countries (including non-immigrants). These differences in tumor characteristics between immigrant groups should be taken into consideration when planning preventive or screening strategies.

• Larsen, Inger Kristin; Møller, Bjørn; Ursin, Giske & Robsahm, Trude Eid (2022). Trends of cancer in Norway 1953–2021. Norsk Epidemiologi. ISSN 0803-2491. 30(1-2), p. 5–17. doi: 10.5324/nje.v30i1-2.4971. Full text in Research Archive
• Lilleborge, Marie; Falk, Ragnhild Sørum; Hovda, Tone; Holmen, Marit Muri; Ursin, Giske & Hofvind, Solveig (2021). Patterns of aggressiveness: risk of progression to invasive breast cancer by mammographic features of calcifications in screen-detected ductal carcinoma in situ. Acta Radiologica. ISSN 0284-1851. 63(5), p. 586–595. doi: 10.1177/02841851211006319. Full text in Research Archive Show summary

  Background Mammographic features of calcifications on mammograms showing invasive breast cancer are associated with survival. Less is known about mammographic features and progression to invasive breast cancer among women treated for ductal carcinoma in situ (DCIS). Purpose To investigate mammographic features of calcifications in screen-detected DCIS in women who later did and did not get diagnosed with invasive breast cancer. Material and Methods This registry-based nested case-control study analyzed data from women with screen-detected DCIS in BreastScreen Norway, 1995–2016. Within this cohort of women with DCIS, those who were later diagnosed with invasive breast cancer (cases) were matched (1:2) to women who were not diagnosed with invasive breast cancer (controls) after their DCIS and by the end of 2016. Information on mammographic features were collected by a national radiological review, where screening mammograms were reviewed locally at each of the 16 breast centers in Norway. We used conditional logistic regression analysis to estimate associations between mammographic features of calcifications in the DCIS mammogram and the risk of subsequent invasive breast cancer. Results We found a higher risk of invasive breast cancer associated with fine linear branching (casting) morphology (odds ratio 20.0; 95% confidence interval [CI] 2.5–158.9) compared to fine linear or fine pleomorphic morphology. Regional or diffuse distribution showed an odds ratio of 2.8 (95% CI 1.0–8.2) compared to segmental or linear distribution. Conclusion Mammographic features of calcifications in screen-detected DCIS were of influence on the risk of invasive breast cancer. Unfavorable characteristics of DCIS were fine linear branching morphology, and regional or diffuse distribution.

• Storås, Anne Marie Holck; Fosså, Sophie Dorothea; Ursin, Giske & Kulle, Bettina (2021). Survival trends for patients with primary metastatic prostate cancer before and after the introduction of new antitumor drugs. Prostate Cancer and Prostatic Diseases. ISSN 1365-7852. p. 1–6. doi: 10.1038/s41391-021-00445-x. Full text in Research Archive
• Enerly, Espen; Holmstrøm, Lena; Skog, Anna; Knudsen, Kristin Oterholt; Nygård, Jan Franz & Møller, Bjørn [Show all 7 contributors for this article] (2021). Inspire: A new opportunity for cancer pharmacoepidemiology research. Norsk Epidemiologi. ISSN 0803-2491. 29(1-2), p. 29–33. doi: 10.5324/nje.v29i1-2.4043. Full text in Research Archive
• Lilleborge, Marie; Falk, Ragnhild Sørum; Sørlie, Therese; Ursin, Giske & Hofvind, Solveig (2021). Can breast cancer be stopped? Modifiable risk factors of breast cancer among women with a prior benign or premalignant lesion. International Journal of Cancer. ISSN 0020-7136. 149(6), p. 1247–1256. doi: 10.1002/ijc.33680. Full text in Research Archive Show summary

  Physical inactivity, high postmenopausal body mass index, alcohol consumption and use of menopausal hormone therapy are established risk factors for breast cancer. Less is known about whether these factors influence the risk of progression of benign and premalignant breast lesions to invasive breast cancer. This registry-based cohort study was based on women with a precancerous lesion who were followed for breast cancer. The cohort consisted of 11 270 women with a benign lesion, 972 women with hyperplasia with atypia and 2379 women with carcinoma in situ diagnosed and treated after participation in BreastScreen Norway, 2006-2016. Information on breast cancer risk factors was collected by a questionnaire administered with the invitation letter. Cox regression analysis was used to estimate the association between breast cancer and physical activity, body mass index, alcohol consumption, tobacco smoking and menopausal hormone therapy, adjusted for age. During follow-up, 274 women with a benign lesion, 34 women with hyperplasia with atypia and 118 women with carcinoma in situ were diagnosed with invasive breast cancer. We observed an increased risk of breast cancer associated with use of menopausal hormone therapy for women with a benign or premalignant lesion. Alcohol consumption and tobacco smoking showed suggestive increased risk of breast cancer among women with a benign lesion. We were only to a limited degree able to identify associations between modifiable risk factors of breast cancer and the disease among women with a precancerous lesion, and a larger study is needed to confirm or refute associations.

• Johannessen, Tom Børge; Smeland, Sigbjørn; Aaserud, Stein; Buanes, Eirik Alnes; Skog, Anna & Ursin, Giske [Show all 7 contributors for this article] (2021). COVID-19 in Cancer Patients, Risk Factors for Disease and Adverse Outcome, a Population-Based Study From Norway. Frontiers in Oncology. 11. doi: 10.3389/fonc.2021.652535. Full text in Research Archive Show summary

  Background Cancer has been suggested as a risk factor for severe outcome of SARS-CoV-2 infection. In this population-based study we aimed to identify factors associated with higher risk of COVID-19 and adverse outcome. Methods Data on all confirmed SARS-CoV-2 positive patients in the period January 1 to May 31, 2020 were extracted from the Norwegian Surveillance System for Communicable Diseases. Data on cancer and treatment was available from the Cancer Registry of Norway, the Norwegian Patient Registry and the Norwegian Prescription Database. Deaths due to COVID-19 were extracted from the Cause of Death Registry. From the Norwegian Intensive Care and Pandemic Registry we retrieved data on admittance to hospital and intensive care. We determined rates of COVID-19 disease in cancer patients and the rest of the population. We also ran multivariate analyses adjusting for age and gender. Results A total of 8 410 patients were diagnosed with SARS-CoV-2 infection in Norway during the study period, of which 547 (6.5%) were cancer patients. Overall, we found similar age adjusted rates of COVID-19 in the population with cancer as in the population without cancer. Unadjusted analysis showed that patients having undergone major surgery within the past 3 months had an increased risk of COVID-19 while we did not find increased Odds Ratio (OR) related to other oncological treatment modalities. No patients treated with stem cell or bone marrow transplant were diagnosed with COVID-19. The fatality rate of COVID-19 among cancer patients was 0.10. This was similar to non-cancer patients, when adjusting for age and sex with OR (95% CI) for death= 0.99 (0.68–1.42). Patients with distant metastases had significantly increased OR of death due to COVID-19 disease of 9.31 (95% CI 2.60–33.34). For the combined outcome death and/or admittance to hospital due to COVID-19, we found significant two-fold increased risk estimates for patients diagnosed with cancer less than one 1 year ago (OR 2.08, 95% CI 1.14–3.80), for those treated with anti-cancer drugs during the past 3 months (OR 1.80, 95% CI 1.07–3.01) and for patients undergoing major surgery during the past 3 months (OR 2.19, 95% CI 1.40–3.44).

• Lee, Eunjung; Kawaguchi, Eric S.; Zhang, Juanjuan; Kim, Sue E.; Deapen, Dennis & Liu, Lihua [Show all 13 contributors for this article] (2021). Bariatric surgery in patients with breast and endometrial cancer in California: population-based prevalence and survival. Surgery for Obesity and Related Diseases. ISSN 1550-7289. 18(1), p. 42–52. doi: 10.1016/j.soard.2021.09.017. Full text in Research Archive
• Johansson, Anna; Trewin, Cassia Bree; Fredriksson, Irma; Reinertsen, Kristin Valborg; Russnes, Hege Elisabeth Giercksky & Ursin, Giske (2021). In modern times, how important are breast cancer stage, grade and receptor subtype for survival: a population-based cohort study. Breast Cancer Research. ISSN 1465-5411. 23(17). doi: 10.1186/s13058-021-01393-z. Full text in Research Archive Show summary

  Background In breast cancer, immunohistochemistry (IHC) subtypes, together with grade and stage, are well-known independent predictors of breast cancer death. Given the immense changes in breast cancer treatment and survival over time, we used recent population-based data to test the combined influence of IHC subtypes, grade and stage on breast cancer death. Methods We identified 24,137 women with invasive breast cancer aged 20 to 74 between 2005 and 2015 in the database of the Cancer Registry of Norway. Kaplan-Meier curves, mortality rates and adjusted hazard ratios for breast cancer death were estimated by IHC subtypes, grade, tumour size and nodal status during 13 years of follow-up. Results Within all IHC subtypes, grade, tumour size and nodal status were independent predictors of breast cancer death. When combining all prognostic factors, the risk of death was 20- to 40-fold higher in the worst groups compared to the group with the smallest size, low grade and ER+PR+HER2− status. Among node-negative ER+HER2− tumours, larger size conferred a significantly increased breast cancer mortality. ER+PR−HER2− tumours of high grade and advanced stage showed particularly high breast cancer mortality similar to TNBC. When examining early versus late mortality, grade, size and nodal status explained most of the late (> 5 years) mortality among ER+ subtypes. Conclusions There is a wide range of risks of dying from breast cancer, also across small breast tumours of low/intermediate grade, and among node-negative tumours. Thus, even with modern breast cancer treatment, stage, grade and molecular subtype (reflected by IHC subtypes) matter for prognosis.

• Larønningen, Siri; Skog, Anna; Gulbrandsen, Johanne; Johannessen, Tom Børge; Larsen, Inger Kristin & Møller, Bjørn [Show all 7 contributors for this article] (2021). Betydelig nedgang i kreftdiagnostikk under covid-19-pandemien. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 141(4). doi: 10.4045/tidsskr.21.0068. Full text in Research Archive
• Søraas, Arne Vasli; Kalleberg, Karl Trygve; Dahl, John Arne; Søraas, Camilla Lund; Myklebust, Tor Åge & Axelsen, Eyvind Wærsted [Show all 12 contributors for this article] (2021). Persisting symptoms three to eight months after non-hospitalized COVID-19, a prospective cohort study. PLOS ONE. 16(8), p. 1–13. doi: 10.1371/journal.pone.0256142. Full text in Research Archive Show summary

  Long-COVID-19 is a proposed syndrome negatively affecting the health of COVID-19 patients. We present data on self-rated health three to eight months after laboratory confirmed COVID-19 disease compared to a control group of SARS-CoV-2 negative patients. We followed a cohort of 8786 non-hospitalized patients who were invited after SARS-CoV-2 testing between February 1 and April 15, 2020 (794 positive, 7229 negative). Participants answered online surveys at baseline and follow-up including questions on demographics, symptoms, risk factors for SARS-CoV-2, and self-rated health compared to one year ago. Determinants for a worsening of self-rated health as compared to one year ago among the SARS-CoV-2 positive group were analyzed using multivariate logistic regression and also compared to the population norm. The follow-up questionnaire was completed by 85% of the SARS-CoV-2 positive and 75% of the SARS-CoV-2 negative participants on average 132 days after the SARS-CoV-2 test. At follow-up, 36% of the SARS-CoV-2 positive participants rated their health “somewhat” or “much” worse than one year ago. In contrast, 18% of the SARS-CoV-2 negative participants reported a similar deterioration of health while the population norm is 12%. Sore throat and cough were more frequently reported by the control group at follow-up. Neither gender nor follow-up time was associated with the multivariate odds of worsening of self-reported health compared to one year ago. Age had an inverted-U formed association with a worsening of health while being fit and being a health professional were associated with lower multivariate odds. A significant proportion of non-hospitalized COVID-19 patients, regardless of age, have not returned to their usual health three to eight months after infection.

• Kværner, Ane Sørlie; Birkeland, Einar Elvbakken; Bucher-Johannessen, Cecilie; Vinberg, Elina; Nordby, Jan Inge & Kangas, Harri [Show all 27 contributors for this article] (2021). The CRCbiome study: a large prospective cohort study examining the role of lifestyle and the gut microbiome in colorectal cancer screening participants. BMC Cancer. 21. doi: 10.1186/s12885-021-08640-8. Full text in Research Archive Show summary

  Background: Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, current screening methods are either hampered by invasiveness or suboptimal performance, limiting their effectiveness as primary screening methods. To aid in the development of a non-invasive screening test with improved sensitivity and specificity, we have initiated a prospective biomarker study (CRCbiome), nested within a large randomized CRC screening trial in Norway. We aim to develop a microbiome-based classification algorithm to identify advanced colorectal lesions in screening participants testing positive for an immunochemical fecal occult blood test (FIT). We will also examine interactions with host factors, diet, lifestyle and prescription drugs. The prospective nature of the study also enables the analysis of changes in the gut microbiome following the removal of precancerous lesions. Methods: The CRCbiome study recruits participants enrolled in the Bowel Cancer Screening in Norway (BCSN) study, a randomized trial initiated in 2012 comparing once-only sigmoidoscopy to repeated biennial FIT, where women and men aged 50–74 years at study entry are invited to participate. Since 2017, participants randomized to FIT screening with a positive test result have been invited to join the CRCbiome study. Self-reported diet, lifestyle and demographic data are collected prior to colonoscopy after the positive FIT-test (baseline). Screening data, including colonoscopy findings are obtained from the BCSN database. Fecal samples for gut microbiome analyses are collected both before and 2 and 12 months after colonoscopy. Samples are analyzed using metagenome sequencing, with taxonomy profiles, and gene and pathway content as primary measures. CRCbiome data will also be linked to national registries to obtain information on prescription histories and cancer relevant outcomes occurring during the 10 year follow-up period. Discussion: The CRCbiome study will increase our understanding of how the gut microbiome, in combination with lifestyle and environmental factors, influences the early stages of colorectal carcinogenesis. This knowledge will be crucial to develop microbiome-based screening tools for CRC. By evaluating biomarker performance in a screening setting, using samples from the target population, the generalizability of the findings to future screening cohorts is likely to be high.

• Hjerkind, Kirsti Vik; Larsen, Inger Kristin; Aaserud, Stein; Møller, Bjørn & Ursin, Giske (2020). Cancer incidence in non-immigrants and immigrants in Norway. Acta Oncologica. ISSN 0284-186X. 59(11), p. 1275–1283. doi: 10.1080/0284186X.2020.1817549. Full text in Research Archive Show summary

  Background Major cancers are associated with lifestyle, and previous studies have found that the non-immigrant populations in the Nordic countries have higher incidence rates of most cancers than the immigrant populations. However, rates are changing worldwide – so these differences may disappear with time. Here we present recent cancer incidence rates among immigrant and non-immigrant men and women in Norway and investigate whether previous differences still exist. Material and methods We took advantage of a recent change in the Norwegian Cancer Registry regulations that allow for the registry to have information on country of birth. The number of person years for 2014–2018 was aggregated for every combination of sex, five-year age-group and country of birth, by summing up each year’s population in these groups. The number of cancer cases was then counted for the same groups, and age-standardised incidence rates calculated by weighing the age-specific incidence rates by the Nordic and World standard populations. Further, we calculated incidence rate ratios using the non-immigrant population as a reference. Results Immigrants from Eastern Europe, the Middle East, Africa and Asia had lower incidence of total cancer compared to the non-immigrant population in Norway and immigrants born in the other Nordic or high-income countries. However, some cancers were more common in certain immigrant groups. Asian men and women had threefold the incidence of liver cancer than non-immigrant men and women. Men from the other Nordic countries and from Eastern Europe had higher lung cancer rates than non-immigrant men. Conclusion National registries should continuously monitor and present cancer incidence stratified on important population subgroups such as country of birth. This can help assess population subgroup specific needs for cancer prevention and treatment, and could eventually help reduce the morbidity and mortality of cancer.

• Nilbert, Mef; Thomsen, Linda Aagaard; Jensen, Jens Winther; Møller, Henrik; Borre, Michael & Nordmark, Arvid Widenlou [Show all 11 contributors for this article] (2020). The power of empirical data; lessons from the clinical registry initiatives in Scandinavian cancer care. Acta Oncologica. ISSN 0284-186X. 59(11), p. 1343–1356. doi: 10.1080/0284186X.2020.1820573. Full text in Research Archive Show summary

  Background In Scandinavia, there is a strong tradition for research and quality monitoring based on registry data. In Denmark, Norway and Sweden, 63 clinical registries collect data on disease characteristics, treatment and outcome of various cancer diagnoses and groups based on process-related and outcome-related variables. Aim We describe the cancer-related clinical registries, compare organizational structures and quality indicators and provide examples of how these registries have been used to monitor clinical performance, develop prediction models, assess outcome and provide quality benchmarks. Further, we define unmet needs such as inclusion of patient-reported outcome variables, harmonization of variables and barriers for data sharing. Results and conclusions The clinical registry framework provides an empirical basis for evidence-based development of high-quality and equitable cancer care. The registries can be used to follow implementation of new treatment principles and monitor patterns of care across geographical areas and patient groups. At the same time, the lessons learnt suggest that further developments and coordination are needed to utilize the full potential of the registry initiative in cancer care.

• Trewin, Cassia Bree; Hjerkind, Kirsti Vik; Johansson, Anna; Strand, Bjørn Heine; Kiserud, Cecilie E. & Ursin, Giske (2020). Socioeconomic inequalities in stage-specific breast cancer incidence: a nationwide registry study of 1.1 million young women in Norway, 2000–2015. Acta Oncologica. ISSN 0284-186X. 59(11), p. 1284–1290. doi: 10.1080/0284186X.2020.1753888. Full text in Research Archive
• Randel, Kristin Ranheim; Schult, Anna Lisa; Botteri, Edoardo; Hoff, Geir; Bretthauer, Michael & Ursin, Giske [Show all 20 contributors for this article] (2020). Colorectal cancer screening with repeated fecal immunochemical test versus sigmoidoscopy: baseline results from a randomized trial. Gastroenterology. ISSN 0016-5085. 160(4), p. 1085–1096. doi: 10.1053/j.gastro.2020.11.037. Full text in Research Archive Show summary

  Background and aims: The comparative effectiveness of sigmoidoscopy and fecal immunochemical testing (FIT) for colorectal cancer (CRC) screening is unknown. Methods: Individuals aged 50-74 years living in South-East Norway were randomly invited between 2012 and 2019 to either once-only flexible sigmoidoscopy or FIT screening every second year. Colonoscopy was recommended after sigmoidoscopy if any polyp ≥10 mm, ≥ three adenomas, any advanced adenomas, or CRC was found or subsequent to FIT > 15 μg hemoglobin/g feces. Data for this report were obtained after complete recruitment in both groups and included two full FIT rounds and part of the third round. Outcome measures were participation, neoplasia detection, and adverse events. Age-standardized detection rates and age-adjusted odds ratios (OR) were calculated. Results: We included 139,291 individuals; 69,195 randomized to sigmoidoscopy and 70,096 to FIT. Participation rate was 52% for sigmoidoscopy, 58% in the first FIT round and 68% for three cumulative FIT rounds. Compared to sigmoidoscopy, detection rate for CRC was similar in the first FIT round (0.25% vs 0.27%, OR 0.92, 95% CI 0.75-1.13), but higher after three FIT rounds (0.49% vs 0.27%, OR 1.87, 95% CI 1.54-2.27). Advanced adenoma detection rate was lower in the first FIT round compared to sigmoidoscopy, 1.4% vs 2.4% (OR 0.57, 95% CI 0.53-0.62), but higher after three cumulative FIT rounds, 2.7% vs 2.4% (OR 1.14, 95% CI 1.05-1.23). There were 33 (0.05%) serious adverse events in the sigmoidoscopy group compared to 47 (0.07%) in the FIT group (p =.13). Conclusion: Participation was higher and more CRC and advanced adenomas were detected with repeated FIT compared to sigmoidoscopy. The risk of perforation and bleeding was comparable. Clinicaltrials.gov (NCT01538550).

• Lee, Eunjung; Kinninger, April; Ursin, Giske; Tseng, Chiu-Chen; Hurley, Susan & Wang, Miaomiao [Show all 11 contributors for this article] (2020). Serum levels of commonly detected persistent organic pollutants and per- and polyfluoroalkyl substances (PFASs) and mammographic density in postmenopausal women. International Journal of Environmental Research and Public Health (IJERPH). ISSN 1661-7827. 17(2), p. 1–10. doi: 10.3390/ijerph17020606. Full text in Research Archive Show summary

  There are little epidemiological data on the impact of persistent organic pollutants (POPs) and endocrine disruptors on mammographic density (MD), a strong predictor of breast cancer. We assessed MD in 116 non-Hispanic white post-menopausal women for whom serum concentrations of 23 commonly detected chemicals including 3 polybrominated diphenyl ethers (PBDEs), 8 per- and polyfluoroalkyl substances (PFASs), and 12 polychlorinated biphenyls (PCBs) had been measured. Linear regression analyses adjusting for potential confounders were used to examine the associations between the levels of the chemical compounds, modeled as continuous and dichotomized (above/below median) variables, and square-root-transformed MD. None of the associations were statistically significant after correcting for multiple testing. Prior to correction for multiple testing, all chemicals with un-corrected p-values &lt; 0.05 had regression coefficients less than zero, suggesting inverse associations between increased levels and MD, if any. The smallest p-value was observed for PCB-153 (regression coefficient for above-median vs. below-median levels: −0.87, un-corrected p = 0.008). Neither parity nor body mass index modified the associations. Our results do not support an association between higher MD and serum levels of PBDEs, PCBs, or PFASs commonly detected in postmenopausal women.

• Trewin, Cassia Bree; Johansson, Anna; Vik, Kirsti Lund; Strand, Bjørn Heine; Kiserud, Cecilie E. & Ursin, Giske (2020). Stage‑specific survival has improved for young breast cancer patients since 2000: but not equally. Breast Cancer Research and Treatment. ISSN 0167-6806. 182(2), p. 477–489. doi: 10.1007/s10549-020-05698-z. Full text in Research Archive Show summary

  Purpose The stage-specific survival of young breast cancer patients has improved, likely due to diagnostic and treatment advances. We addressed whether survival improvements have reached all socioeconomic groups in a country with universal health care and national treatment guidelines. Methods Using Norwegian registry data, we assessed stage-specific breast cancer survival by education and income level of 7501 patients (2317 localized, 4457 regional, 233 distant and 494 unknown stage) aged 30–48 years at diagnosis during 2000–2015. Using flexible parametric models and national life tables, we compared excess mortality up to 12 years from diagnosis and 5-year relative survival trends, by education and income as measures of socioeconomic status (SES). Results Throughout 2000–2015, regional and distant stage 5-year relative survival improved steadily for patients with high education and high income (high SES), but not for patients with low education and low income (low SES). Regional stage 5-year relative survival improved from 85 to 94% for high SES patients (9% change; 95% confidence interval: 6, 13%), but remained at 84% for low SES patients (0% change; − 12, 12%). Distant stage 5-year relative survival improved from 22 to 58% for high SES patients (36% change; 24, 49%), but remained at 11% for low SES patients (0% change; − 19, 19%). Conclusions Regional and distant stage breast cancer survival has improved markedly for high SES patients, but there has been little survival gain for low SES patients. Socioeconomic status matters for the stage-specific survival of young breast cancer patients, even with universal health care.

• Larsen, Inger Kristin; Myklebust, Tor Åge; Babigumira, Ronnie; Vinberg, Elina; Møller, Bjørn & Ursin, Giske (2020). Education, income and risk of cancer: results from a Norwegian registry-based study. Acta Oncologica. ISSN 0284-186X. 59(11), p. 1300–1307. doi: 10.1080/0284186X.2020.1817548. Full text in Research Archive
• Schoemaker, Minouk J.; Nichols, Hazel B.; Wright, Lauren B.; Brook, Mark N.; Jones, Michael E. & O'Brien, Katie M. [Show all 43 contributors for this article] (2020). Adult weight change and premenopausal breast cancer risk: A prospective pooled analysis of data from 628,463 women. International Journal of Cancer. ISSN 0020-7136. p. 1–10. doi: 10.1002/ijc.32892. Full text in Research Archive Show summary

  Early‐adulthood body size is strongly inversely associated with risk of premenopausal breast cancer. It is unclear whether subsequent changes in weight affect risk. We pooled individual‐level data from 17 prospective studies to investigate the association of weight change with premenopausal breast cancer risk, considering strata of initial weight, timing of weight change, other breast cancer risk factors and breast cancer subtype. Hazard ratios (HR) and 95% confidence intervals (CI) were obtained using Cox regression. Among 628,463 women, 10,886 were diagnosed with breast cancer before menopause. Models adjusted for initial weight at ages 18–24 years and other breast cancer risk factors showed that weight gain from ages 18–24 to 35–44 or to 45–54 years was inversely associated with breast cancer overall (e.g., HR per 5 kg to ages 45–54: 0.96, 95% CI: 0.95–0.98) and with oestrogen‐receptor(ER)‐positive breast cancer (HR per 5 kg to ages 45–54: 0.96, 95% CI: 0.94–0.98). Weight gain from ages 25–34 was inversely associated with ER‐positive breast cancer only and weight gain from ages 35–44 was not associated with risk. None of these weight gains were associated with ER‐negative breast cancer. Weight loss was not consistently associated with overall or ER‐specific risk after adjusting for initial weight. Weight increase from early‐adulthood to ages 45–54 years is associated with a reduced premenopausal breast cancer risk independently of early‐adulthood weight. Biological explanations are needed to account for these two separate factors.

• Lee, Eunjung; Doanvo, Namphuong; Lee, MiHee; Soe, Zayar; Lee, Alice & Van, Doan [Show all 11 contributors for this article] (2020). Immigration history, lifestyle characteristics, and breast density in the Vietnamese American Women’s Health Study: a cross-sectional analysis. Cancer Causes and Control. ISSN 0957-5243. 31(2), p. 127–138. doi: 10.1007/s10552-019-01264-1. Full text in Research Archive
• Hoff, Geir; Ursin, Giske; Løberg, Magnus; Lange, Thomas de; Skovlund, Eva & Holme, Øyvind (2019). Continuous development of colorectal cancer screening programs. Acta Oncologica. ISSN 0284-186X. 3(1), p. 822–823. doi: 10.1080/0284186X.2019.1588475. Full text in Research Archive Show summary

  Colorectal cancer (CRC) screening programs are far from perfect. Many crucial questions remain, yet expensive CRC screening services are implemented throughout the world without a plan on how to evaluate and improve the service. The time is ripe for improving the design of CRC screening programs.

• Andreassen, Trude; Hansen, Bo Terning; Engesæter, Birgit Øvstebø; Hashim, Dana; Støer, Nathalie Charlotte & Trope, Ameli [Show all 9 contributors for this article] (2019). Psychological effect of cervical cancer screening when changing primary screening method from cytology to high-risk human papilloma virus testing. International Journal of Cancer. ISSN 0020-7136. 145(1), p. 29–39. doi: 10.1002/ijc.32067. Full text in Research Archive Show summary

  From 2015, Norway has implemented high‐risk human papilloma virus (hrHPV) testing in primary screening for cervical cancer. Women aged 34–69 years, living in four counties, have been pseudo‐randomly assigned (1:1 randomization) to either hrHPV testing every 5 years (followed by cytology if hrHPV is positive), or cytology testing every 3 years (followed by hrHPV testing if low‐grade cytology is detected). We compared anxiety and depression scores among participants by screening arm and results. In total, 1,008 women answered a structured questionnaire that included the validated Patient Health Questionnaire‐4 (PHQ‐4). The Relative Risk Ratio (RRR) of mild vs. normal anxiety and depression scores, and moderate/severe vs. normal anxiety and depression scores, were estimated by multinomial logistic regression with 95% confidence intervals (95% CIs). Compared to women who were screened with cytology, women randomized to hrHPV testing were not more likely to have mild anxiety and depression scores (RRR 0.96, CI 0.70–1.31) nor more likely to have moderate/severe anxiety and depression scores (RRR 1.14, CI 0.65–2.02). Women with five different combinations of abnormal screening test results were not more likely to have mild or moderate/severe vs. normal anxiety and depression scores than women with normal screening results. The likelihood of having abnormal long‐term (4–24 months after the screening) anxiety or depression scores among women 34 years and older was not affected by screening method or screening results. The results of our study suggest that a change to hrHPV testing in primary screening would not increase psychological distress among participants.

• Dench, Evenda; Bond-Smith, Daniela; Darcey, Ellie; Lee, Grant; Aung, Ye K. & Chan, Ariane [Show all 32 contributors for this article] (2019). Measurement challenge: Protocol for international case-control comparison of mammographic measures that predict breast cancer risk. BMJ Open. 9:e031041(12), p. 1–6. doi: 10.1136/bmjopen-2019-031041. Full text in Research Archive
• Nichols, Hazel B.; Schoemaker, Minouk J.; Cai, Jianwen; Xu, Jiawei; Wright, Lauren B. & Brook, Mark N. [Show all 43 contributors for this article] (2019). Breast cancer risk after recent childbirth: A pooled analysis of 15 prospective studies. Annals of Internal Medicine. ISSN 0003-4819. 170(1), p. 22–30. doi: 10.7326/M18-1323. Full text in Research Archive Show summary

  Background: Parity is widely recognized as protective for breast cancer, but breast cancer risk may be increased shortly after childbirth. Whether this risk varies with breastfeeding, family history of breast cancer, or specific tumor subtype has rarely been evaluated. Objective: To characterize breast cancer risk in relation to recent childbirth. Design: Pooled analysis of individual-level data from 15 prospective cohort studies. Setting: The international Premenopausal Breast Cancer Collaborative Group. Participants: Women younger than 55 years. Measurements: During 9.6 million person-years of follow-up, 18 826 incident cases of breast cancer were diagnosed. Hazard ratios (HRs) and 95% CIs for breast cancer were calculated using Cox proportional hazards regression. Results: Compared with nulliparous women, parous women had an HR for breast cancer that peaked about 5 years after birth (HR, 1.80 [95% CI, 1.63 to 1.99]) before decreasing to 0.77 (CI, 0.67 to 0.88) after 34 years. The association crossed over from positive to negative about 24 years after birth. The overall pattern was driven by estrogen receptor (ER)–positive breast cancer; no crossover was seen for ER-negative cancer. Increases in breast cancer risk after childbirth were pronounced when combined with a family history of breast cancer and were greater for women who were older at first birth or who had more births. Breastfeeding did not modify overall risk patterns. Limitations: Breast cancer diagnoses during pregnancy were not uniformly distinguishable from early postpartum diagnoses. Data on human epidermal growth factor receptor 2 (HER2) oncogene overexpression were limited. Conclusion: Compared with nulliparous women, parous women have an increased risk for breast cancer for more than 20 years after childbirth. Health care providers should consider recent childbirth a risk factor for breast cancer in young women. Primary Funding Source: The Avon Foundation, the National Institute of Environmental Health Sciences, Breast Cancer Now and the UK National Health Service, and the Institute of Cancer Research.

• Bergholtz, Helga; Lien, Tonje Gulbrandsen; Ursin, Giske; Holmen, Marit Muri; Helland, Åslaug & Sørlie, Therese [Show all 7 contributors for this article] (2019). A Longitudinal Study of the Association between Mammographic Density and Gene Expression in Normal Breast Tissue. Journal of mammary gland biology and neoplasia. ISSN 1083-3021. 24(2), p. 163–175. doi: 10.1007/s10911-018-09423-x. Full text in Research Archive Show summary

  High mammographic density (MD) is associated with a 4–6 times increase in breast cancer risk. For post-menopausal women,MD often decreases over time, but little is known about the underlying biological mechanisms. MD reflects breast tissuecomposition, and may be associated with microenvironment subtypes previously identified in tumor-adjacent normal tissue. Currently, these subtypes have not been explored in normal breast tissue. We obtained biopsies from breasts of healthy women at two different time points several years apart and performed microarray gene expression analysis. At time point 1, 65 samples with both MD and gene expression were available. At time point 2, gene expression and MD data were available from 17 women, of which 11 also had gene expression data available from the first time point. We validated findings from our previous study; negative correlation between RBL1 and MD in post-menopausal women, indicating involvement of the TGFβ pathway. We also found that breast tissue samples from women with a large decrease in MD sustained higher expression of genes in the histone family H4. In addition, we explored the previously defined active and inactive microenvironment subtypes and demonstrated that normal breast samples of the active subtype had characteristics similar to the claudin-low breast cancer subtype. Breast biopsies from healthy women are challenging to obtain, but despite a limited sample size, we have identified possible mechanisms relevant for changes in breast biology and MD over time that may be of importance for breast cancer risk and tumor initiation.

• Ma, Huiyan; Malone, Kathleen E; McDonald, Jill A.; Marchbanks, Polly A.; Ursin, Giske & Strom, Brian L. [Show all 10 contributors for this article] (2019). Pre-diagnosis alcohol consumption and mortality risk among black women and white women with invasive breast cancer. BMC Cancer. 19(1). doi: 10.1186/s12885-019-5991-8. Full text in Research Archive Show summary

  Background Alcohol consumption is associated with increased risk of breast cancer; however, its association with subsequent risk of breast cancer death is unclear. Methods We followed 4523 women with complete information on relevant risk factors for mortality; these women were 35 to 64 years of age when diagnosed with incident invasive breast cancer between 1994 and 1998. During follow up (median, 8.6 years), 1055 women died; 824 died from breast cancer. The information on alcohol consumption before diagnosis was collected shortly after breast cancer diagnosis (average: 5.1 months) during an in-person interview which used a structured questionnaire. Multivariable Cox proportional hazards regression models provided hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer-specific mortality, mortality due to causes other than breast cancer, and all-cause mortality associated with alcohol consumption from age 15 years until breast cancer diagnosis and during recent periods of time prior to breast cancer diagnosis. Results Average weekly alcohol consumption from age 15 years until breast cancer diagnosis was inversely associated with breast cancer-specific mortality (Ptrend = 0.01). Compared to non-drinkers, women in the highest average weekly alcohol consumption category (≥7 drinks/week) had 25% lower risk of breast cancer-specific mortality (HR = 0.75, 95% CI = 0.56–1.00). Breast cancer mortality risk was also reduced among women in the highest average weekly alcohol consumption category in two recent time periods (5-year period ending 2-years prior to breast cancer diagnosis, HR = 0.74, 95% CI = 0.57–0.95; 2-year period immediately prior to breast cancer diagnosis: HR = 0.73, 95% CI = 0.56–0.95). Furthermore, analyses of average weekly alcohol consumption by beverage type from age 15 years until breast cancer diagnosis suggested that wine consumption was inversely associated with breast cancer-specific mortality risk (wine Ptrend = 0.06, beer Ptrend = 0.24, liquor Ptrend = 0.74). No association with any of these alcohol consumption variables was observed for mortality risk due to causes other than breast cancer. Conclusions Overall, we found no evidence that alcohol consumption before breast cancer diagnosis increases subsequent risk of death from breast cancer.

• Kreimer, Aimée R.; Ferreiro-Iglesias, Aida; Nygård, Mari; Bender, Noemi; Schroeder, Lea & Hildesheim, Alan [Show all 40 contributors for this article] (2019). Timing of HPV16-E6 antibody seroconversion before OPSCC: Findings from the HPVC3 consortium. Annals of Oncology. ISSN 0923-7534. 30(8), p. 1335–1343. doi: 10.1093/annonc/mdz138. Full text in Research Archive Show summary

  Background Human papillomavirus type 16 (HPV16)-E6 antibodies are detectable in peripheral blood before diagnosis in the majority of HPV16-driven oropharyngeal squamous cell carcinoma (OPSCC), but the timing of seroconversion is unknown. Patients and methods We formed the HPV Cancer Cohort Consortium which comprises nine population cohorts from Europe, North America and Australia. In total, 743 incident OPSCC cases and 5814 controls provided at least one pre-diagnostic blood sample, including 111 cases with multiple samples. Median time between first blood collection and OPSCC diagnosis was 11.4 years (IQR = 6–11 years, range = 0–40 years). Antibodies against HPV16-E6 were measured by multiplex serology (GST fusion protein based Luminex assay). Results HPV16-E6 seropositivity was present in 0.4% of controls (22/5814; 95% CI 0.2% to 0.6%) and 26.2% (195/743; 95% CI 23.1% to 29.6%) of OPSCC cases. HPV16-E6 seropositivity increased the odds of OPSCC 98.2-fold (95% CI 62.1–155.4) in whites and 17.2-fold (95% CI 1.7–170.5) in blacks. Seropositivity in cases was more frequent in recent calendar periods, ranging from 21.9% pre-1996 to 68.4% in 2005 onwards, in those with blood collection near diagnosis (lead time <5 years). HPV16-E6 seropositivity increased with lead time: 0.0%, 13.5%, 23.7%, and 38.9% with lead times of >30 years (N = 24), 20–30 years (N = 148), 10–20 years (N = 228), and <10 years (N = 301 cases) (p-trend < 0.001). Of the 47 HPV16-E6 seropositive cases with serially-collected blood samples, 17 cases seroconverted during follow-up, with timing ranging from 6 to 28 years before diagnosis. For the remaining 30 cases, robust seropositivity was observed up to 25 years before diagnosis. Conclusions The immune response to HPV16-driven tumorigenesis is most often detectable several decades before OPSCC diagnosis. HPV16-E6 seropositive individuals face increased risk of OPSCC over several decades.

• Kulle, Bettina; Støer, Nathalie Charlotte; Martinsen, Jan Ivar; Ursin, Giske; Weiderpass, Elisabete & Thoresen, G. Hege [Show all 10 contributors for this article] (2019). Identification of potential carcinogenic and chemopreventive effects of prescription drugs: A protocol for a Norwegian registry-based study. BMJ Open. 9:e028504(4), p. 1–7. doi: 10.1136/bmjopen-2018-028504. Full text in Research Archive Show summary

  <i>Introduction</i> - Surveillance of unintended effects of pharmaceuticals (pharmacovigilance or drug safety) is crucial, as knowledge of rare or late side effects is limited at the time of the introduction of new medications into the market. Side effects of drugs may involve increased or decreased risk of cancer, but these typically appear after a long induction period. This fact, together with low incidences of many cancer types, limits the usefulness of traditional pharmacovigilance strategies, primarily based on spontaneous reporting of adverse events, to identify associations between drug use and cancer risk. Postmarketing observational pharmacoepidemiological studies are therefore crucial in the evaluation of drug-cancer associations.<p> <p><i>Methods and analysis</i> - The main data sources in this project will be the Norwegian Prescription Database and the Cancer Registry of Norway. The underlying statistical model will be based on a multiple nested case–control design including all adult (~200 000) incident cancer cases within the age-range 18–85 years from 2007 through 2015 in Norway as cases. 10 cancer-free population controls will be individually matched to these cases with respect to birth year, sex and index date (date of cancer diagnosis). Drug exposure will be modelled as chronic user/non-user by counting prescriptions, and cumulative use by summarising all dispensions’ daily defined doses over time. Conditional logistic regression models adjusted for comorbidity (National Patient Register), socioeconomic parameters (Statistics Norway), concomitant drug use and, for female cancers, reproduction data (Medical Birth Registry), will be applied to identify drug-use–cancer-risk associations.<p> <p><i>Ethics and dissemination</i> - The study is approved by the regional ethical committee and the Norwegian data protection authority. Results of the initial screening step and analysis pipeline will be described in a key paper. Subsequent papers will report the evaluation of identified signals in replication studies. Results will be published in peer-reviewed journals, at scientific conferences and through press releases.

• Lilleborge, Marie; Falk, Ragnhild Sørum; Russnes, Hege Elisabeth Giercksky; Sauer, Torill; Ursin, Giske & Hofvind, Solveig (2019). Risk of breast cancer by prior screening results among women participating in BreastScreen Norway. Cancer. ISSN 0008-543X. 125(19), p. 3330–3337. doi: 10.1002/cncr.32330. Full text in Research Archive Show summary

  Background: This registry‐based cohort study followed women who participated in the organized breast cancer screening program in Norway, BreastScreen Norway, in 1995‐2016. Incidence rates and incidence rate ratios were used to estimate absolute and relative risks of breast cancer associated with PSRs. Histopathological characteristics of subsequent breast cancers were presented by PSRs. Results: This study included 762,643 women with up to 21 years of follow‐up. In comparison with negatively screened women, increased incidence rate ratios of 1.8, 2.0, 2.9, and 3.8 were observed after negative additional imaging, for benign biopsy, for hyperplasia with atypia, and for carcinoma in situ, respectively. Subsequent breast cancers did not differ in tumor diameter or histological grade, whereas the proportion of lymph node–positive breast cancers decreased as the presumed malignancy potential of PSRs increased. Conclusions: The risk of subsequent breast cancer increased with the presumed malignancy potential of PSRs, whereas the tumor characteristics of subsequent cancers did not differ except for the lymph node status. Women with screen‐detected benign lesions or hyperplasia with atypia might benefit from more frequent screening.

• Johansson, Anna; Trewin, Cassia Bree; Vik, Kirsti Lund; Ellingjord-Dale, Merete; Johannessen, Tom Børge & Ursin, Giske (2019). Breast cancer-specific survival by clinical subtype after 7 years follow-up of young and elderly women in a nationwide cohort. International Journal of Cancer. ISSN 0020-7136. 144(6), p. 1251–1261. doi: 10.1002/ijc.31950. Full text in Research Archive Show summary

  Age and tumor subtype are prognostic factors for breast cancer survival, but it is unclear which matters the most. We used population‐based data to address this question. We identified 21,384 women diagnosed with breast cancer at ages 20–89 between 2005 and 2015 in the Cancer Registry of Norway. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A‐like (ER+PR+HER2‐), luminal B‐like HER2‐negative (ER+PR‐HER2‐), luminal B‐like HER2‐positive (ER+PR+/‐HER2+), HER2‐positive (ER‐PR‐HER2+) and triple‐negative (TNBC) (ER‐PR‐HER2‐). Cox regression estimated hazard ratios (HR) for breast cancer‐specific 7‐year survival by age and subtype, while adjusting for year, grade, TNM stage and treatment. Young women more often had HER2‐positive and TNBC tumors, while elderly women (70–89) more often had luminal A‐like tumors. Compared to age 50–59, young women had doubled breast cancer‐specific mortality rate (HR = 2.26, 95% CI 1.81–2.82), while elderly had two to five times higher mortality rate (70–79: HR = 2.25, 1.87–2.71; 80–89: HR = 5.19, 4.21–6.41). After adjustments, the association was non‐significant among young women but remained high among elderly. Young age was associated with increased breast cancer‐specific mortality among luminal A‐like subtype, while old age was associated with increased mortality in all subtypes. Age and subtype were strong independent prognostic factors. The elderly always did worse, also after adjustment for subtype. Tumor‐associated factors (subtype, grade and stage) largely explained the higher breast cancer‐specific mortality among young. Future studies should address why luminal A‐like subtype is associated with a higher mortality rate in young women.

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• Geleijnse, Gijs; Backes, Claudine; Chirlaque, Maria Dolores; Sloep, Matthijs; Navarro, Esteve Rodon & Šekerija, Mario [Show all 8 contributors for this article] (2026). Every cancer patient counts: strengthening European population-based cancer registries to improve cancer control. The Lancet Regional Health - Europe. 70. doi: 10.1016/j.lanepe.2026.101855.
• Larsen, Inger Kristin; Aagnes, Bjarte; Breivik, Simen; Hestad, Johanne Jerven; Jakobsen, Elisabeth & Johannessen, Tom Børge [Show all 14 contributors for this article] (2026). Cancer in Norway 2025. Cancer incidence, mortality, survival and prevalence in Norway. Full text in Research Archive Show summary

  Key messages • In 2025, 40364 new cancer cases were reported. This is an increase from the figures reported in Cancer in Norway 2024. For the first time, Nor way has surpassed 40000 new cancer cases in a single year. • The most frequently occurring cancers in males are prostate cancer, non-melanoma skin cancer, lung cancer, colon cancer and melanoma of the skin. • In females, the most frequently occurring can cers are breast, lung, colon and skin cancers (non melanoma and melanoma). • The Norwegian population is growing, and older individuals constitute an increasingly larger pro portion of the population. Both of these factors suggest that we can expect a rise in the number of cancer cases. Tounderstandhowtherisk ofcancer evolves, it is crucial to account for these changes by examining age-standardised rates. When comparing the age-standardised rates for all cancers combined in the last five-year period (2021–2025) with the previous one (2016–2020), we observe a slight reduction in rates among males, while there has been a small increase among females. For males, we also observe that the rates for sev eral major cancer sites, such as prostate, lung, and colorectal, have decreased. In females, there has been a reduction in lung cancer and gynaecolo gical cancer rates, with a particularly significant decline in cervical cancer rates. Skin cancers (non-melanoma and melanoma) continue to show a substantial increase in both sexes, and there is also a significant rise in female breast cancer rates the last decade. • By the end of 2025, 359257 individuals were alive after having had at least one cancer diagnosis at some point in time. • In 2025, the number of cancer-related deaths was 11703. Lung cancer, colon cancer, pancreatic can cer, prostate cancer, and female breast cancer to gether accounted for half of these deaths. • The five-year relative survival varies from less than 10 percent for pancreatic cancer (excluding neur oendocrine neoplasms) to nearly 100 percent for testicular cancer. Thereisalso significantvariation in relative survival between different stages. Fortunately, there has been a substantial improve ment in five-year relative survival over the last 10–15 years for cancers with a poor prognosis such as lung cancer, stomach cancer, and oesopha geal cancer. For all cancer types combined, the five-year relative survival rate is 78 percent, mean ing that nearly 8 out of 10 cancer patients survive their cancer disease for five years or more.

• Søraas, Arne Vasli Lund; Brunvoll, Sonja Hjellegjerde; Nygaard, Anders Benteson; Dahl, John Arne & Ursin, Giske (2024). Post-COVID-19 condition symptoms 6–12 months after hospitalisation in Wuhan. The Lancet. ISSN 0140-6736. 403(10434), p. 1336–1336. doi: 10.1016/S0140-6736(24)00414-8. Full text in Research Archive
• Svendsen, Karianne; Leithe, Sigrid; Myklebust, Tor Åge; Eriksen, Hege Randi; Meland, Anders & Nes, Lise Solberg [Show all 8 contributors for this article] (2024). Associations between lifestyle factors and health-related quality of life in breast cancer patients and controls. Norsk tidsskrift for ernæring (NTFE). ISSN 1503-5034. 22(5), p. 89–89. doi: 10.18261/ntfe.22.5.127. Full text in Research Archive
• Svendsen, Karianne; Nes, Lise Solberg; Meland, Anders; Larsson, Ine Marie; Gjelsvik, Ylva M. & Børøsund, Elin [Show all 17 contributors for this article] (2023). Coping After Breast Cancer: Protocol for a Randomized Controlled Trial of Stress Management eHealth Interventions. JMIR Research Protocols. 12. doi: 10.2196/47195. Full text in Research Archive Show summary

  Background: One-third or more of breast cancer survivors report stress and other psychological and physical complaints that can negatively impact their quality of life. Psychosocial stress management interventions, shown to mitigate the negative impact of these complaints, can now be delivered as accessible and convenient (for the patient and provider) eHealth interventions. In this randomized controlled trial (RCT), Coping After Breast Cancer (CABC), 2 modified versions of the stress management eHealth intervention program StressProffen were created: one with predominantly cognitive behavioral stress management content (StressProffen-cognitive behavioral therapy intervention [StressProffen-CBI]) and another with predominantly mindfulness-based stress management content (StressProffen-mindfulness-based intervention [StressProffen-MBI]). Objective: This study aims to investigate the effects in breast cancer survivors of using StressProffen-CBI and StressProffen-MBI compared with a control group (treatment as usual). Methods: Women diagnosed with breast cancer (stage I-III, unequivocally human epidermal growth factor receptor 2–positive or estrogen receptor-negative tumors) or ductal carcinoma in situ (DCIS) aged 21-69 years who completed the Cancer Registry of Norway–initiated health survey on quality of life are invited to the CABC trial about 7 months after diagnosis. Women who give consent to participate are randomized (1:1:1) to either the StressProffen-CBI, StressProffen-MBI, or control group. Both StressProffen interventions consist of 10 modules of stress management content delivered through text, sound, video, and images. The primary outcome is between-group changes in perceived stress at 6 months, assessed with Cohen 10-item Perceived Stress Scale. The secondary outcomes comprise changes in quality of life, anxiety, depression, fatigue, sleep, neuropathy, coping, mindfulness, and work-related outcomes approximately 1, 2, and 3 years after diagnosis. Long-term effects of the interventions on work participation, comorbidities, relapse or new cancers, and mortality will be assessed using data from national health registries. Results: Recruitment is scheduled from January 2021 to May 2023. The goal is to recruit 430 participants (100 in each group). As of April 14 2023, 428 participants have been enrolled. Conclusions: The CABC trial is possibly the largest ongoing psychosocial eHealth RCT in patients with breast cancer. If 1 or both interventions prove to be effective in reducing stress and improving psychosocial and physical complains, the StressProffen eHealth interventions could be beneficial, inexpensive, and easily implementable tools for breast cancer survivors when coping with late effects after cancer and cancer treatments.

• Børøsund, Elin; Meland, Anders; Eriksen, Hege Randi; Rygg, Christine Marie; Ursin, Giske & Nes, Lise Solberg (2023). CBT- and Mindfulness-based Support for Breast Cancer Survivors: Development of two Digital Stress-management Interventions. Full text in Research Archive
• Nygård, Mari; Burger, Emily Annika; Nygård, Ståle; Tropé, Ameli; Falkenthal, Thea Eline Hetland & Berland, Jannicke Mohr [Show all 10 contributors for this article] (2023). Skal vi screene og konisere inn i evigheten – eller bytte HPV-vaksine? Full text in Research Archive Show summary

  Norge blir ikke det første landet som eliminerer livmorhalskreft – til det er vi ikke ambisiøse nok, tidlig nok. Men vi kan fortsatt innrette oss bedre for å forebygge enda mer – og mer kostnadseffektivt.

• Berstad, Paula; Schult, Anna Lisa; Hoff, Geir Svein; Ursin, Giske & Randel, Kristin Ranheim (2023). Sosiale forskjeller i forprosjektet for tarmkreftscreening. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(5). doi: 10.4045/tidsskr.22.0760. Full text in Research Archive
• Tasken, Kjetil; Russnes, Hege Elisabeth Giercksky; Aas, Eline; Bjørge, Line; Blix, Egil Støre & Ahlquist, Terje C. [Show all 116 contributors for this article] (2022). A national precision cancer medicine implementation initiative for Norway. Nature Medicine. ISSN 1078-8956. 28(5), p. 885–887. doi: 10.1038/s41591-022-01777-4. Full text in Research Archive
• Ursin, Giske (2022). Cancer Registry of Norway – full speed ahead. Developments over the past decade. Norsk Epidemiologi. ISSN 0803-2491. 30(1-2), p. 155–160. doi: 10.5324/nje.v30i1-2.4991. Full text in Research Archive
• Hofvind, Solveig Sand-Hanssen; Mangerud, Gunhild; Holen, åsne Sørlien & Ursin, Giske (2022). Overdiagnosis – exemplified with mammographic screening. Norsk Epidemiologi. ISSN 0803-2491. 30(1-2), p. 77–82. doi: 10.5324/nje.v30i1-2.4981. Full text in Research Archive Show summary

  The goal of organized mammographic screening is early detection of breast cancer and thereby to reduce disease-specific morbidity and mortality. One disadvantage is overdiagnosis. The World Health Organization's International Agency for Research on Cancer defines overdiagnosis in mammographic screening as the diagnosis of a breast cancer as a result of screening that would not have been diagnosed in the woman’s lifetime if screening had not taken place. We cannot identify which tumors are overdiagnosed or accurately quantify the extent of overdiagnosis in mammographic screening. Analyzing data from large groups will give an estimate, but the result will depend, among other things, on the calculation method, control group, follow-up time, and type of data used (individual data versus aggregate numbers). Although subtypes of breast cancer with different prognosis can be defined, the growth patterns within the same subtype can change over time, and it is therefore not possible at the time of diagnosis to identify which tumours are overdiagnosed and do not require treatment. All women who are diagnosed with breast cancer are thus offered treatment. The term overdiagnosis is complex and difficult to understand. In some contexts, it is used as an umbrella term for various phenomena such as misdiagnosis, false positive screening results or overtreatment. Overdiagnosis in mammographic screening does not include misdiagnosis or false positives. Increased knowledge in the population and the use of more advanced examination techniques means that more breast cancer tumours are now detected at an early stage and thus increases the risk of overdiagnosis and overtreatment. New treatment methods reduce breast cancer mortality, also for advanced disease, but often at the cost of side and late effects of the treatment. The future goal is more precise screening and diagnostics, and more personalized treatment. Nevertheless, some overdiagnosis and overtreatment is probably the price we have to pay to save women from dying of breast cancer.

• Liu, Fei-Chih; Veierød, Marit Bragelien; Kjærheim, Kristina; Robsahm, Trude Eid; Ghiasvand, Reza & Babigumira, Ronnie [Show all 11 contributors for this article] (2021). Excess risk of male breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a possible link to extreme night shift work? Breast Cancer Research. ISSN 1465-5411. doi: 10.1186/s13058-021-01485-w. Full text in Research Archive
• Liu, Fei-Chih; Veierød, Marit B.; Kjærheim, Kristina; Robsahm, Trude E.; Ghiasvand, Reza & Babigumira, Ronnie [Show all 11 contributors for this article] (2021). Excess risk of male breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a possible link to extreme night shift work? Breast Cancer Research. ISSN 1465-5411. 23(1). doi: 10.1186/s13058-021-01485-w. Full text in Research Archive
• Bentzen, Heidi Beate; Castro, Rosa; Fears, Robin; Griffin, George; Meulen, Volker ter & Ursin, Giske (2021). Remove obstacles to sharing health data with researchers outside of the European Union. 27, p. 1329–1333. doi: 10.1038/s41591-021-01460-0. Full text in Research Archive Show summary

  COVID-19 has shown that international collaborations and global data sharing are essential for health research, but legal obstacles are preventing data sharing for non–pandemic-related research among public researchers across the world, with potentially damaging effects for citizens and patients.

• Ursin, Giske & Bentzen, Heidi Beate (2021). Rettslige utfordringer struper medisinsk forskning. Full text in Research Archive
• Ursin, Giske & Bentzen, Heidi Beate (2021). Open science and sharing personal data widely–legally impossible for Europeans? Acta Oncologica. ISSN 0284-186X. doi: 10.1080/0284186X.2021.1995894. Full text in Research Archive
• Kværner, Ane Sørlie; Knudsen, Markus Dines; Hjartåker, Anette; Henriksen, Hege; Blomhoff, Rune & Hoff, Geir Svein [Show all 9 contributors for this article] (2021). Kost, livsstil og tarmscreening. Norsk tidsskrift for ernæring (NTFE). ISSN 1503-5034. Full text in Research Archive
• Svendsen, Karianne; Knudsen, Markus Dines; Berstad, Paula; Ursin, Giske; Larsen, Inger Kristin & Kværner, Ane Sørlie (2020). Kreft i Norge 2020: Hvor stor rolle spiller kost og livsstil? Norsk tidsskrift for ernæring (NTFE). ISSN 1503-5034. Full text in Research Archive
• Johansson, Anna L.V. & Ursin, Giske (2020). Author's reply to: “Detection by screening introduces biases into survival estimates for luminal A-like breast cancer patients”. International Journal of Cancer. ISSN 0020-7136. 146(6), p. 1767–1768. doi: 10.1002/ijc.32699. Full text in Research Archive
• Ursin, Giske (2019). Cancer registration in the era of modern oncology and GDPR. Acta Oncologica. ISSN 0284-186X. 58(11), p. 1547–1548. doi: 10.1080/0284186X.2019.1657586. Full text in Research Archive
• Andreassen, Trude; Melnic, Adriana; Figueiredo, Rejane Augusta de Oliveira; Moen, Kåre; Şuteu, Ofelia & Nicula, Florian [Show all 8 contributors for this article] (2019). Correction to: Attendance to cervical cancer screening among Roma and non-Roma women living in North-Western region of Romania (International Journal of Public Health, (2018), 63, 5, (609-619), 10.1007/s00038-018-1107-5). International Journal of Public Health. ISSN 1661-8556. 64(6), p. 977–978. doi: 10.1007/s00038-019-01263-8. Full text in Research Archive
• Ursin, Giske; Malila, Nea; Chang-Claude, Jenny; Gunter, Marc; Kaaks, Rudolf & Kampman, Ellen [Show all 19 contributors for this article] (2019). Sharing data safely while preserving privacy. The Lancet. ISSN 0140-6736. 394(10212), p. 1902–1902. doi: 10.1016/S0140-6736(19)32603-0. Full text in Research Archive
• Ursin, Giske; Stenbeck, Magnus; Chang-Claude, Jenny; Gunter, Marc; Kaaks, Rudolf & Kampman, Ellen [Show all 19 contributors for this article] (2019). Data must be shared—also with researchers outside of Europe. The Lancet. ISSN 0140-6736. 394(10212), p. 1902–1903. doi: 10.1016/S0140-6736(19)32633-9. Full text in Research Archive
• Larsen, Inger Kristin; Møller, Bjørn; Johannesen, Tom Børge; Robsahm, Trude Eid; Larønningen, Siri & Nilssen, Yngvar [Show all 12 contributors for this article] (2025). Cancer in Norway 2024- Cancer incidence, mortality, survival and prevalence in Norway. Folkehelseinstituttet. Full text in Research Archive
• Griffin, George; Meulen, Volker ter; Albert, Adelin; Bentzen, Heidi Beate; Boiten, Jan-Willem & Danesh, John [Show all 22 contributors for this article] (2021). International Sharing of Personal Health Data for Research. The ALLEA, EASAC and FEAM joint initiative on resolving the barriers of transferring public sector data outside the EU/EEA. ALLEA, EASAC and FEAM. ISSN 9783804742499. Full text in Research Archive

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