Michael Bretthauer

• Basso, Trude; Bjerke, Lars Martin; Bretthauer, Michael; Christiansen, Ola; Dahl, Torbjørn & Fosse, Erik Torgeir [Show all 14 contributors for this article] (2026). Towards sustainable implementation of robotic surgery: an interregional strategic framework from Norway. Journal of Robotic Surgery. ISSN 1863-2483. 20(1), p. 1–5. doi: 10.1007/s11701-026-03521-3. Full text in Research Archive Show summary

  Robot‑assisted soft‑tissue surgery (RAS) is embedded in many healthcare systems, yet large‑scale adoption has often proceeded without coordinated governance, resulting in variation in access, training standards, and outcome reporting. This policy perspective summarises the findings and recommendations of an interregional expert group commissioned by Norway's four Regional Health Authorities to develop a strategic framework for sustainable implementation of RAS within a publicly funded specialist healthcare system. Key challenges identified include unclear indication selection, heterogeneous training standards, fragmented procurement practices, incomplete lifecycle costing, and limited systematic outcome monitoring. Core recommendations comprise prioritisation of procedures with demonstrated clinical value, standardised lifecycle cost assessment, coordinated procurement, accredited training pathways, and mandatory data registration. The Norwegian framework illustrates how governance, evidence generation, and workforce planning can be aligned to promote sustainable implementation of robotic surgery. Although developed within a public health system, several principles are transferable to other healthcare contexts.

• Piovani, Daniele; Figlioli, Gisella; Nikolopoulos, Georgios K.; Tsilidis, Konstantinos K.; Aghemo, Alessio & Hassan, Cesare [Show all 9 contributors for this article] (2026). Global, regional, and national burden of colorectal cancer attributable to central obesity: a population attributable fraction analysis. BMC Medicine. 24(1). doi: 10.1186/s12916-026-04858-0. Full text in Research Archive Show summary

  Background Central obesity is a major risk factor for colorectal cancer (CRC) and may better reflect obesity-related risk than body mass index (BMI). Its global burden, however, remains poorly quantified. We aimed to estimate the number and proportion of CRC cases attributable to central obesity in 2022 across global, regional, and national levels. Methods We estimated population attributable fractions (PAFs) by combining sex-specific prevalence of central obesity from national surveys with pooled relative risks from meta-analysis. Central obesity was defined as elevated waist circumference using standardised sex- and ethnicity-specific thresholds, accounting for variation in definitions via probabilistic modelling. We addressed missing data through multiple imputation. CRC incidence estimates for 2022 were obtained from GLOBOCAN for 185 countries. Monte Carlo simulations propagated uncertainty in exposure prevalence and risk estimates. Results In 2022, an estimated 311 418 (95% uncertainty interval 242 603–378 880) CRC cases were attributable to central obesity, corresponding to a global PAF of 16.2% (12.6–19.7). PAFs were higher in females (18.2%, 13.0–23.3) than in males (14.5%, 9.6–19.3), though age-standardised rates (ASRs) were slightly higher in males. The highest PAF was in North America, and the highest ASRs in Australia–New Zealand and northern Europe. PAFs and ASRs declined with decreasing income levels among males but not females. Regional variation in sex differences was substantial, with higher female PAFs in parts of Africa and Asia, and smaller or reversed gaps in high-income settings. In high-income countries, the estimated 10-year CRC risk at screening age (55–69 years) was 1.32% in males with central obesity versus 0.90% in those without, and 0.92% versus 0.64% in females, corresponding to one excess CRC case per 236 (180–353) men and 357 (279–502) women. Conclusions Central obesity accounts for a substantial share of the global CRC burden, with large geographical variability. Applying established waist circumference thresholds in surveillance and incorporating central obesity into individual risk stratification may inform more effective CRC screening and prevention strategies.

• Botteri, Edoardo; Holme, Øyvind; Løberg, Magnus; Bretthauer, Michael; Kalager, Mette & Randel, Kristin Ranheim [Show all 7 contributors for this article] (2026). Twenty-Three–Year Benefits of Sigmoidoscopy Screening for Colorectal Cancer A Randomized Trial. Annals of Internal Medicine. ISSN 0003-4819. 179(6), p. 804–811. doi: 10.7326/annals-25-05456. Full text in Research Archive Show summary

  Background: Meta-analyses of randomized trials have shown that sigmoidoscopy screening reduces colorectal cancer (CRC) incidence and death for 15 years. Objective: To report the benefits of sigmoidoscopy after 23 years. Design: Randomized controlled trial. (NORCCAP [Norwegian Colorectal Cancer Prevention], ClinicalTrials.gov: NCT00119912) Setting: Population of Oslo and Telemark County, Norway. Participants: Persons aged 50 to 64 years without CRC at randomization. Intervention: Screening with once-only sigmoidoscopy, with or without 1 fecal immunochemical test, or no screening. Measurements: Colorectal cancer incidence and death. Results: A total of 100 210 persons were randomly assigned, and 98 654 were included in intention-to-screen analyses: 20 552 in the screening group and 78 102 in the no-screening group. Participation with screening was 61.4% in men and 64.7% in women. In men, the 23-year cumulative risk for CRC was 4.3% in the screening group and 6.0% in the no-screening group, corresponding to a risk difference of −1.7 percentage points (95% CI, −2.2 to −1.2 percentage points). In women, the corresponding risks were 4.2% and 4.7%, yielding a risk difference of −0.5 percentage points (CI, −1.0 to −0.01 percentage points). In men, the 23-year cumulative risk for CRC death was 1.4% in the screening group and 2.2% in the no-screening group, corresponding to a risk difference of −0.8 percentage points (CI, −1.1 to −0.5 percentage points). In women, the corresponding risks were 1.3% and 1.4%, yielding a risk difference of −0.1 percentage points (CI, −0.3 to 0.1 percentage points). The effect was strongest for rectosigmoid cancer. The addition of fecal blood testing to sigmoidoscopy did not change screening benefits. Limitation: Follow-up through national registries. Conclusion: Offering sigmoidoscopy screening in Norway reduced CRC incidence more in men than in women and reduced CRC death only in men.

• Kaminski, Michal F; Kalager, Mette; Løberg, Magnus; Emilsson, Louise; Macios, Anna & Samy, Faye [Show all 22 contributors for this article] (2026). Long-term effects of colonoscopy screening on colorectal cancer incidence and mortality: a multicountry, population-based randomised controlled trial. The Lancet. ISSN 0140-6736. doi: 10.1016/s0140-6736(26)00508-8. Full text in Research Archive Show summary

  Background We previously reported the 10-year effects of colonoscopy screening on colorectal cancer incidence and mortality. Here, we report the effects after 13 years of follow-up. Methods In this multicountry, population-based randomised controlled trial, 84 583 men and women aged 55–64 years at enrolment from Norway, Poland, and Sweden were randomly allocated (1:2) to colonoscopy screening or no screening and analysed. The primary outcomes were colorectal cancer incidence and mortality after 10–15 years of follow-up in intention-to-screen analyses, with first analysis after 10 years, and repeated every other year or at longer intervals. This trial is registered with ClinicalTrials.gov, NCT00883792, and is ongoing. Findings At 13 years of follow-up, colorectal cancer incidence was 375 colorectal cancers (1·46%) of 28 217 individuals in the screening group and 912 colorectal cancers (1·80%) of 56 366 individuals in the no-screening group. The risk ratio (RR) was 0·81 (95% CI 0·71–0·90) in intention-to-screen analyses and 0·55 (0·33–0·81) in per-protocol analyses. The risk for proximal colorectal cancer was 129 (0·51%) in the screening group versus 283 (0·56%) in the no-screening group (RR 0·91 [0·71–1·09]), and the risk for distal colorectal cancer was 224 (0·87%) in the screening group versus 563 (1·11%) in the no-screening group (RR 0·79 [0·65–0·89]; interaction p<0·0001). In men, the colorectal cancer risk was 214 (1·69%) of 14 154 in the screening group and 541 (2·19%) of 28 247 in the no-screening group (RR 0·77 [0·64 to –0·88]); in women, the risk was 161 (1·24%) of 14 063 in the screening group versus 371 (1·43%) of 28 119 in the no-screening group (RR 0·87 [0·70 to 1·02]; interaction p<0·0001). Colorectal cancer mortality was 106 (0·41%) of 28 217 in the screening group and 236 (0·47%) of 56 366 in the no-screening group (intention-to-screen RR 0·88 [0·68–1·08], per-protocol RR 0·70 [0·26–1·25]). The observed colorectal cancer mortality in the non-screening group (0·47%) was substantially lower than expected at the time of designing the trial (0·82%). Interpretation One colonoscopy significantly reduced colorectal cancer incidence but not mortality over 13 years. Colorectal cancer mortality was lower in both study groups than when the trial was designed.

• Rognstad, Øyvind Bakken; Botteri, Edoardo; Hoff, Geir Svein; Bretthauer, Michael; Nguyen, Dung-Hong & Schult, Anna Lisa [Show all 8 contributors for this article] (2026). Use of claims data to identify adverse events after colonoscopy in a randomised colorectal cancer screening trial in Norway: a cross-sectional study. BMJ Open. 16(1), p. 1–8. doi: 10.1136/bmjopen-2025-109883. Full text in Research Archive Show summary

  Objectives Accurate identification of adverse events after colonoscopy is essential for quality assurance in colorectal cancer (CRC) screening. Review of medical records is labour intensive as adverse events are infrequent. The object of this study was to investigate the accuracy of claims data in identifying adverse events after colonoscopy in CRC screening. Design Cross-sectional, retrospective. Setting and participants Males and females aged 50–74 years were randomised to once-only sigmoidoscopy or biennial faecal immunochemical test in a CRC screening trial at two screening centres in Norway. Participants in the present study underwent follow-up colonoscopy from 2012 to April 2020 after initial positive screening test. We reviewed medical records for adverse events within 30 days following 11 205 colonoscopies. Primary and secondary outcome measures The primary outcome of the study was to assess the sensitivity of claims data from the Norwegian Patient Registry to identify lower gastrointestinal bleeding using emergency contact International Statistical Classification of Diseases and Related Health Problems 10th Revision diagnostic code sets under two definitions: a stringent definition (codes explicitly identifying bleeding) and a broad definition (including suggestive codes). Secondary outcome measures included the sensitivity to identify perforation using a stringent and a broad definition. Additionally, we assessed whether incorporating procedure codes and non-emergency contacts improved accuracy. Results 87 cases of lower gastrointestinal bleeding and eight perforations were confirmed. Sensitivity for bleeding differed between the centres (p<0.001). At centre 1, sensitivity was 48.6% (95% CI 31.9% to 65.6%) using the stringent and 89.2% (95% CI 74.6% to 97.0%) using the broad definition. At centre 2, sensitivity was 36.0% (95% CI 22.9% to 50.8%) and 50.0% (95% CI 35.5% to 64.5%), respectively. Combined sensitivity for perforation was 37.5% (95% CI 8.5% to 75.5%) using the stringent and 62.5% (95% CI 24.5% to 91.5%) using the broad definition. Adding procedure codes and non-emergency contacts slightly increased sensitivity but increased false positives. Conclusions Use of claims data underestimated adverse event rates following colonoscopy. Difference in coding practice across hospitals underscores the need for standardised reporting in screening programmes. Trial registration number NCT01538550 .

• Bretthauer, Michael; Ahmed, Jabed; Antonelli, Giulio; Beaumont, Hanneke; Beg, Sabina & Benson, Ariel [Show all 23 contributors for this article] (2025). Use of computer-assisted detection (CADe) colonoscopy in colorectal cancer screening and surveillance: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement. Endoscopy. ISSN 0013-726X. 57(06), p. 667–673. doi: 10.1055/a-2543-0370. Full text in Research Archive Show summary

  Summary and Recommendation This statement conveys the European Society of Gastrointestinal Endoscopy (ESGE) position on the use of computer-aided detection (CADe) with artificial intelligence (AI) during colonoscopy for colorectal cancer (CRC) screening or surveillance. The ESGE position is informed by the BMJ Rapid Recommendation initiative and the approach of the MAGIC Evidence Ecosystem Foundation; these include systematic reviews of currently available evidence, supplemented by microsimulation modeling and patient values and preferences, for the benefits and harms of AI CADe devices during colonoscopy. ESGE convened a panel of European experts for this Position Statement. On December 18, 2024, panel members voted on their preferred recommendation between two choices about CADe during colonoscopy for indications of CRC screening or polyp surveillance. Out of 19 eligible votes, 13 (68.4%) voted to recommend CADe for colonoscopy, and six panel members (31.6%) voted against. Therefore, the current ESGE statement is: Recommendation The panel believes that most well-informed patients who have already decided to undergo colonoscopy for screening or surveillance would favor CADe assistance during colonoscopy. This is due to the potential benefits, although limited, of reduction in colorectal cancer incidence and mortality. This recommendation is weak, because the evidence is limited with considerable uncertainty of the evidence estimates, the absolute benefits for colorectal cancer incidence and mortality are small, and there is a patient burden associated with CADe (more polyp overdiagnosis and more colonoscopy surveillance).

• Ahmad, Omer F.; Mori, Yuichi; Bretthauer, Michael; Dourado, Daniel A.; Hassan, Cesare & Bisschops, Raf [Show all 20 contributors for this article] (2025). The Legal and Ethical Framework for Artificial Intelligence in Gastrointestinal Endoscopy: A World Endoscopy Organization International Consensus Statement. Annals of Internal Medicine. ISSN 0003-4819. 179(2), p. 270–275. doi: 10.7326/annals-25-03415. Full text in Research Archive
• Massimi, Davide; Carlini, Luca; Mori, Yuichi; Stefano, Luca Di; Antonelli, Giulio & Rizkala, Tommy [Show all 22 contributors for this article] (2025). Large language model for interpreting the Paris classification of colorectal polyps. Endoscopy International Open. 13(CP). doi: 10.1055/a-2703-0209. Full text in Research Archive Show summary

  Abstract Reporting of colorectal polyp morphology using the Paris classification is often inaccurate. Multimodal large language models (M-LLMs) may support morphological assessment. This study aimed to evaluate the accuracy of an M-LLM (GPT-4o) in classifying colorectal polyp morphology compared with expert and non-expert endoscopists. We used the SUN dataset of colonoscopy videos from 100 unique colorectal polyps, each labeled with the validated Paris classification. An M-LLM (GPT-4o) classified five representative frames per lesion. Three expert and three non-expert endoscopists, blinded to one another, performed the same task. The primary outcome was accuracy in differentiating non-polypoid (IIa/IIc) from polypoid (Is/Ip/Isp) lesions. The secondary outcome was accuracy in differentiating sessile (Is) from pedunculated (Ip/Isp) lesions. Given the exploratory design, no multiplicity correction was applied; point estimates are presented with 95% confidence intervals (CIs), and P values are interpreted descriptively. M-LLM accuracy for differentiating non-polypoid from polypoid lesions was 73% (95% CI 63%-81%), comparable to experts (75%, 65%-83%; P = 0.84) and non-experts (77%, 68%-85%; P = 0.52), with similar sensitivity and specificity. Accuracy for differentiating sessile from pedunculated lesions was 55% (95% CI 42%-67%), lower than experts (76%; P = 0.02) and non-experts (77%; P = 0.01), primarily due to poor specificity (12% vs. experts 82% and non-experts 88%; P < 0.01 for both comparisons). M-LLMs performed comparably to endoscopists in distinguishing non-polypoid from polypoid lesions but failed to reliably identify pedunculated morphology.

• Areia, Miguel; Esposito, Gianluca; Leclercq, Philippe; Romańczyk, Marcin; Zessner-Spitzenberg, Jasmin & Guillena, Pedro G. Delgado [Show all 31 contributors for this article] (2025). Performance measures for upper gastrointestinal endoscopy: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative - Update 2025. Endoscopy. ISSN 0013-726X. 57(11), p. 1268–1297. doi: 10.1055/a-2674-4912. Full text in Research Archive Show summary

  Quality markers and patient experience should be implemented to ensure standardization of practice across upper gastrointestinal (UGI) endoscopy procedures. The set benchmarks ensure high quality procedures are delivered and linked to measurable outcomes. In 2016, the European Society of Gastrointestinal Endoscopy (ESGE), via its Quality Improvement Committee’s UGI Working Group, set a first list of performance measures, including major (key) and minor performance indicators. This paper provides an update on those performance measures, considering the latest literature. Patients referred for a UGI endoscopy should have an appropriate indication and be fasting for ≥ 2 hours for liquids and ≥ 6 hours for solids. For a diagnostic UGI endoscopy, patients should have an allocated time slot of ≥ 20 minutes; adequate reporting should include a mucosal visibility score according to one of the available standardized and validated scales; adequate photodocumentation should include relevant normal anatomical landmarks and all abnormal findings; adequate inspection should include the esophagus, stomach, and duodenum, and should last ≥ 7 minutes from intubation to extubation; adequate terminology should include the description of any abnormal finding according to the available standardized and validated classifications. For patients with nondysplastic Barrett’s esophagus (BE) undergoing surveillance UGI endoscopy, an adequate inspection should take ≥ 1 minute/cm of circumferential extent of Barrett’s epithelium and include the use of chromoendoscopy (acetic acid and/or virtual); biopsies should be taken according to the Seattle protocol. Adequate inspection for a diagnostic UGI endoscopy in patients with a history of ear, nose, and throat, or lung tumors treated with curative intent should include the use of virtual chromoendoscopy. Adequate diagnostic UGI endoscopy for patients evaluated for their risk of gastric cancer should include biopsies taken according to the ESGE management of precancerous conditions and lesions in the stomach (MAPS) guideline. Adequate safety after a therapeutic UGI endoscopy should be assessed by monitoring the incidence of complications. Patients undergoing a diagnostic UGI endoscopy should have their experience measured using a validated scale, to promote a patient-centered and quality-driven environment. Patients with nondysplastic BE or gastric precancerous conditions in an endoscopic surveillance program should be monitored for guideline interval adherence.

• Bretthauer, Michael (2025). Was ist gesichert in der Vorsorge des kolorektalen Karzinoms? Die innere Medizin. ISSN 2731-7080. 66(12), p. 1251–1257. doi: 10.1007/s00108-025-01983-5. Full text in Research Archive Show summary

  Hintergrund Trotz fallender Inzidenz und Mortalität ist Darmkrebs (kolorektales Karzinom) in Deutschland immer noch die zweithäufigste Krebserkrankung bei Frauen (nach Brustkrebs) und die dritthäufigste bei Männern (nach Prostata- und Lungenkrebs). Darmkrebs eignet sich gut für Vorsorge oder Früherkennung mittels Screening. Die zwei vornehmlich empfohlenen Tests sind die Koloskopie und der fäkale immunchemische Test (FIT; Stuhltest auf okkultes Blut). Ziel der Arbeit (Fragestellung) Der vorliegende Beitrag erklärt wichtige konzeptuelle und praktische Unterschiede der angebotenen Screeningtests in Deutschland und beschreibt die neueste Evidenzlage für den Nutzen der am häufigsten angewendeten Screeningmethoden. Ziel des Beitrags ist es, Ärzten Entscheidungshilfen zu geben für Patienten, die sich für das Darmkrebsscreening interessieren. Material und Methoden Gesicherte qualitativ hochwertige Evidenz aus randomisierten Studien zum Nutzen des Darmkrebsscreenings in Bezug auf Inzidenz und Mortalität des kolorektalen Karzinoms. Ergebnisse Das Lebenszeitrisiko in Deutschland, an Darmkrebs zu erkranken, beträgt derzeit 5 % bei Frauen und 6,5 % bei Männern. Laut einer großen randomisierten Studie reduziert eine Vorsorgekoloskopie das Risiko von Darmkrebs über 10 Jahre von 1,2 % auf ungefähr 0,8–0,9 %. Neue Evidenz einer großen spanischen randomisierten Studie zeigt, dass der Nutzen eines FIT-Screenings jedes zweite Jahr als gleichwertig zur einer Koloskopie über 10 Jahre einzuordnen ist. Das Risiko einer Perforation während einer Koloskopie liegt bei ungefähr 0,01 %, und das Risiko einer Blutung bei 0,1 %. Schlussfolgerung Bei der ärztlichen Patientenaufklärung zum Screening wird empfohlen, die oben genannten Zahlen für Nutzen und Risiko heranzuziehen und zu erklären.

• Mori, Yuichi; Wang, Pu; Kamba, Shunsuke; Liu, Lin; Siersema, Peter D. & Hassan, Cesare [Show all 24 contributors for this article] (2025). Addressing Colonoscopy Burden Due to Artificial Intelligence Devices for Polyp Detection. Gastroenterology. ISSN 0016-5085. 170(2), p. 398–400. doi: 10.1053/j.gastro.2025.08.019. Full text in Research Archive
• Spadaccini, Marco; Hassan, Cesare; Mori, Yuichi; Halvorsen, Natalie Grace Mosteiro; Gimeno-García, Antonio Z. & Nakashima, Hirotaka [Show all 42 contributors for this article] (2025). Artificial intelligence and colorectal neoplasia detection performances in patients with positive fecal immunochemical test: Meta-analysis and systematic review. Digestive Endoscopy. ISSN 0915-5635. 37(8), p. 815–823. doi: 10.1111/den.15034. Full text in Research Archive
• Halvorsen, Natalie Grace Mosteiro; Hassan, Cesare; Correale, Loredana; Pilonis, Nastazja Dagny; Helsingen, Lise Mørkved & Spadaccini, Marco [Show all 14 contributors for this article] (2025). Benefits, burden, and harms of computer aided polyp detection with artificial intelligence in colorectal cancer screening: microsimulation modelling study. BMJ Medicine. 4(1). doi: 10.1136/bmjmed-2025-001446. Full text in Research Archive
• Olabintan, Olaolu; Halvorsen, Natalie Grace Mosteiro; Baddeley, Robin; Kudo, Shin Ei; Barua, Ishita & Misawa, Masashi [Show all 21 contributors for this article] (2025). Environmental impact of computer-aided diagnosis in colonoscopy: A carbon footprint assessment of a prospective study cohort. Endoscopy. ISSN 0013-726X. 58(03), p. 303–309. doi: 10.1055/a-2717-8365. Full text in Research Archive Show summary

  Background The environmental impact of computer-aided diagnosis (CADx) in colonoscopy is unknown. The potential to reduce greenhouse gas emissions by limiting unnecessary polypectomies may be offset by emissions associated with CADx devices. We quantified and compared the carbon footprint of colonoscopy with and without CADx. Methods Life-cycle carbon emissions associated with endoscopic snares, polyp traps, histopathology, and CADx devices were estimated using life-cycle assessment software. The effect of CADx was estimated by the carbon dioxide equivalent (CO2e) emissions related to outcomes from a prospective cohort of patients who underwent colonoscopy with optical diagnosis under a leave-in-situ strategy (i.e. rectosigmoid polyps ≤5 mm predicted as non-neoplastic were not removed) with and without CADx assistance. Results We analyzed 1134 individuals (median age 67 years, 59% male) with 1716 colorectal polyps. Colonoscopy with CADx reduced the number of snares and polyp traps from 567 to 543 (difference: 24) and histopathology submissions from 1343 to 1278 (difference: 65). However, the total carbon footprint increased from 832 kg CO2e (95%CI 815 to 847) without CADx to 946 kg CO2e (95%CI 927 to 965) with CADx, corresponding to an absolute increase of 114 kg CO2e (95%CI 80 to 150) or 0.10 kg CO2e per colonoscopy. Conclusion Using CADx under a leave-in-situ strategy increased the environmental burden of colonoscopy.

• Budzyń, Krzysztof; Romańczyk, Marcin; Kitala, Diana; Kołodziej, Paweł; Bugajski, Marek & Adami, Hans Olov [Show all 21 contributors for this article] (2025). Endoscopist deskilling risk after exposure to artificial intelligence in colonoscopy: a multicentre, observational study. The Lancet Gastroenterology and Hepatology. ISSN 2468-1253. 10(10), p. 896–903. doi: 10.1016/S2468-1253(25)00133-5. Full text in Research Archive
• Gjersvik, Petter & Bretthauer, Michael (2025). Avlæring og ferdighetsreduksjon ved bruk av kunstig intelligens. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 145(13). doi: 10.4045/tidsskr.25.0565. Full text in Research Archive
• Young, Jessica C.; Helsingen, Lise Mørkved; Refsum, Erle; Högdén, Amanda; Perrin, Vera & Løberg, Magnus [Show all 20 contributors for this article] (2025). Temporal trends in characteristics and management of inflammatory bowel disease. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 60(5), p. 421–429. doi: 10.1080/00365521.2025.2478166. Full text in Research Archive Show summary

  Background and aims: Inflammatory bowel disease (IBD) requires complex clinical management. Despite substantial advancements in endoscopy and in pharmacotherapies for patients with IBD, it remains unclear how these developments have influenced IBD incidence and clinical care. We aim to describe changes in diagnostic and therapeutic practices in IBD management. Methods: All individuals diagnosed with IBD between 1987 and 2016 were identified from nationwide registries in Norway and Sweden. We performed detailed chart abstractions for a random sample of the cohort. We describe patient characteristics, disease extent, endoscopic practices, pathology diagnostics, pharmacological therapy and surgical management, stratifying by Crohn’s disease (CD) and ulcerative colitis [UC], comparing patients diagnosed before (pre-biologic period, 1987–1999), and after the introduction of biologic drugs (biologic period, 2000–2016). Results: Chart abstraction was completed for 791 individuals (UC: 58.8%, Crohn’s disease: 40.2%, unclassified IBD: 1.0%). Comparing the biologic period to the pre-biologic period, we observed an increase in endoscopies after diagnosis, more frequent colonoscopies, and a decrease in colon resection rates. Among those diagnosed in 2007 or later compared with those diagnosed between 2000 and 2006, there was a higher treatment initiation rate of azathioprine, infliximab and adalimumab within 1 year after diagnosis. Conclusions: Our findings suggest a shift towards more frequent endoscopy, increased use of immunosuppressants and biologics, and decreased colon resection rates in recent periods.

• Halvorsen, Natalie Grace Mosteiro; Barua, Ishita; Kudo, Shin-Ei; Gulati, Shraddha; Misawa, Masashi & Mori, Kensaku [Show all 19 contributors for this article] (2025). Leaving colorectal polyps in situ with endocytoscopy assisted by computer-aided diagnosis: a cost-effectiveness study. Endoscopy. ISSN 0013-726X. 57, p. 611–619. doi: 10.1055/a-2532-9282. Full text in Research Archive
• Pilonis, Nastazja Dagny; Spychalski, Piotr; Kalager, Mette; Løberg, Magnus; Wieszczy, Paulina & Didkowska, Joanna [Show all 12 contributors for this article] (2025). Adenoma Detection Rates by Physicians and Subsequent Colorectal Cancer Risk. Journal of the American Medical Association (JAMA). ISSN 0098-7484. 333(5), p. 400–407. doi: 10.1001/jama.2024.22975. Full text in Research Archive
• Shi, Joy; Løberg, Magnus; Kalager, Mette; Wieszczy, Paulina; Pilonis, Nastazja Dagny & Adami, Hans Olov [Show all 10 contributors for this article] (2025). Effect of colonoscopy screening on risks of colorectal cancer and related death: instrumental variable estimation of per-protocol effects. European Journal of Epidemiology (EJE). ISSN 0393-2990. doi: 10.1007/s10654-025-01209-w. Full text in Research Archive
• Juul, Frederik Emil; Bretthauer, Michael; Johnsen, Peter Holger; Samy, Faye; Tonby, Kristian & Berdal, Jan-Erik [Show all 29 contributors for this article] (2025). Fecal Microbiota Transplantation Versus Vancomycin for Primary Clostridioides difficile Infection : A Randomized Controlled Trial. Annals of Internal Medicine. ISSN 0003-4819. 178(7), p. 940–947. doi: 10.7326/ANNALS-24-03285. Full text in Research Archive
• Anvari, Sama; Dadgar, Kayla; Galts, Ciarán & Bretthauer, Michael (2024). Gastroenterology/Hepatology: What You May Have Missed in 2023. Annals of Internal Medicine. ISSN 0003-4819. 177(5), p. S27–S36. doi: 10.7326/M24-0505. Full text in Research Archive
• Randel, Kristin Ranheim; Schult, Anna Lisa; Botteri, Edoardo; Nawaz, Mobina; Nguyen, Dung-Hong & Holme, Øyvind [Show all 9 contributors for this article] (2024). Impact of inadequate bowel cleansing in sigmoidoscopy screening. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 59(8), p. 1002–1009. doi: 10.1080/00365521.2024.2364213. Full text in Research Archive Show summary

  Background and study aims: Long-time follow-up of sigmoidoscopy screening trials has shown reduced incidence and mortality of colorectal cancer (CRC), but inadequate bowel cleansing may hamper efficacy. The aim of this study was to assess the impact of bowel cleansing quality in sigmoidoscopy screening. Patients and methods: Individuals 50 to 74 years old who had a screening sigmoidoscopy in a population-based Norwegian, randomized trial between 2012 and 2019, were included in this cross-sectional study. The bowel cleansing quality was categorised as excellent, good, partly poor, or poor. The effect of bowel cleansing quality on adenoma detection rate (ADR) and referral to colonoscopy was evaluated by fitting multivariable logistic regression models. Results: 35,710 individuals were included. The bowel cleansing at sigmoidoscopy was excellent in 20,934 (58.6%) individuals, good in 6580 (18.4%), partly poor in 7097 (19.9%) and poor in 1099 (3.1%). The corresponding ADRs were 17.0%, 16.6%, 14.5%, and 13.0%. C

• Nilsen, Jens Aksel; Bernklev, Linn; Bretthauer, Michael; Kalager, Mette; Jodal, Henriette C. & Løberg, Magnus [Show all 9 contributors for this article] (2024). Kirurgisk behandling av benigne kolorektale polypper 2008–21. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(10). doi: 10.4045/tidsskr.23.0722. Full text in Research Archive
• Martínez-Roca, Alejandro; Cubiella, Joaquín; García-Heredia, Anabel; Guill-Berbegal, David; Baile-Maxía, Sandra & Mangas-Sanjuán, Carolina [Show all 23 contributors for this article] (2024). Prediction of metachronous advanced colorectal neoplasia by KRAS mutation in polyps. United European Gastroenterology Journal (UEG Journal). ISSN 2050-6406. doi: 10.1002/ueg2.12667. Full text in Research Archive
• Rognstad, Øyvind Bakken; Botteri, Edoardo; Hoff, Geir Svein; Bretthauer, Michael; Gulichsen, Elisabeth Haagensen & Frigstad, Svein Oskar [Show all 8 contributors for this article] (2024). Adverse events after colonoscopy in a randomised colorectal cancer screening trial. BMJ open gastroenterology. 11(1). doi: 10.1136/bmjgast-2024-001471. Full text in Research Archive Show summary

  Objective: Colonoscopy-related adverse events increase the burden of colorectal cancer (CRC) screening. This cross-sectional study evaluates adverse events during and after colonoscopy in a large, randomised CRC screening trial in Norway comparing sigmoidoscopy to immunochemical testing for faecal blood. Methods: We included all individuals who underwent colonoscopy at two screening centres between 2012 and 2020. From medical records, we retrieved data on adverse events during and within 30 days after colonoscopy and classified them according to the American Society for Gastrointestinal Endoscopy lexicon for endoscopic adverse events. Multivariable logistic regression models were fitted to identify risk factors for adverse events. Results: Of the 10 244 included individuals, 242 (2.4%) had at least one adverse event that was possibly, probably, or definitively related to the colonoscopy. 188 (1.8%) had mild adverse events, 50 (0.49%) had moderate, 3 (0.03%) had severe, and 1 had a fatal adverse event. The m

• Xu, Hui; Bretthauer, Michael; Fang, Fang; Ye, Weimin; Yin, Li & Adami, Hans Olov (2024). Dramatic improvements in outcome following pancreatoduodenectomy for pancreatic and periampullary cancers. British Journal of Cancer. ISSN 0007-0920. 131(4), p. 747–754. doi: 10.1038/s41416-024-02757-w. Full text in Research Archive
• Randel, Kristin Ranheim; Botteri, Edoardo; Lange, Thomas de; Schult, Anna Lisa; Eskeland, Sigrun Losada & El-Safadi, Badboni [Show all 11 contributors for this article] (2024). Performance of Faecal Immunochemical Testing for Colorectal Cancer Screening at Varying Positivity Thresholds. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. 61(1), p. 122–131. doi: 10.1111/apt.18314. Full text in Research Archive Show summary

  Background: The positivity thresholds of faecal immunochemical testing (FIT) in colorectal cancer (CRC) screening vary between countries. Aims: To explore the trade-off between colonoscopies performed, adverse events and lesions detected at different FIT thresholds in a Norwegian CRC screening trial. Methods: We included first participation in biennial FIT screening for 47,265 individuals aged 50-74 years. Individuals with FIT > 15 μg Hb/g faeces were referred for colonoscopy. We estimated the number of colonoscopies, adverse events, screen-detected CRCs, advanced adenomas and serrated lesions expected at FIT thresholds currently or recently used in other European countries ranging between 20 and 150 μg/g. Results: At the 15 μg/g threshold (Norway), 3705 participants underwent colonoscopy, of whom 203 had CRC, 1119 advanced adenomas and 256 advanced serrated lesions. Using a 47 μg/g threshold, 1826 (49.3%) individuals would have undergone colonoscopy, and 154 (75.9%) would have been diagnosed with CRC, 702

• Baile-Maxía, Sandra; Mangas-Sanjuán, Carolina; Ladabaum, Uri; Sánchez-Ardila, Carmen; Sala-Miquel, Noelia & Hassan, Cesare [Show all 10 contributors for this article] (2024). Risk factors for metachronous colorectal cancer or advanced lesions after endoscopic resection of serrated polyps: a systematic review and meta-analysis. Gastrointestinal Endoscopy. ISSN 0016-5107. doi: 10.1016/j.gie.2024.05.021. Full text in Research Archive
• Antonelli, Giulio; Libanio, Diogo; Groof, Albert Jeroen De; Sommen, Fons van der; Mascagni, Pietro & Sinonquel, Pieter [Show all 32 contributors for this article] (2024). QUAIDE - Quality assessment of AI preclinical studies in diagnostic endoscopy. Gut. ISSN 0017-5749. doi: 10.1136/gutjnl-2024-332820. Full text in Research Archive
• Juul, Frederik Emil; Cross, Amanda J.; Schoen, Robert E.; Senore, Carlo; Pinsky, Paul F. & Miller, Eric A. [Show all 17 contributors for this article] (2024). Effectiveness of Colonoscopy Screening vs Sigmoidoscopy Screening in Colorectal Cancer. JAMA Network Open. 7(2). doi: 10.1001/jamanetworkopen.2024.0007. Full text in Research Archive Show summary

  Importance: Randomized clinical screening trials have shown that sigmoidoscopy screening reduces colorectal cancer (CRC) incidence and mortality. Colonoscopy has largely replaced sigmoidoscopy for CRC screening, but long-term results from randomized trials on colonoscopy screening are still lacking. Objective: To estimate the additional screening benefit of colonoscopy compared with sigmoidoscopy. Design, setting, and participants: This comparative effectiveness simulation study pooled data on 358 204 men and women randomly assigned to sigmoidoscopy screening or usual care in 4 randomized sigmoidoscopy screening trials conducted in Norway, Italy, the US, and UK with inclusion periods in the years 1993 to 2001. The primary analysis of the study was conducted from January 19 to December 30, 2021. Intervention: Invitation to endoscopic screening. Main outcomes and measures: Primary outcomes were CRC incidence and mortality. Using pooled 15-year follow-up data, colonoscopy screening effectiveness was estimate

• Bretthauer, Michael; Gerke, Sara; Hassan, Cesare; Ahmad, Omer F. & Mori, Yuichi (2023). The New European Medical Device Regulation: Balancing Innovation and Patient Safety. Annals of Internal Medicine. ISSN 0003-4819. 176(6), p. 844–848. doi: 10.7326/M23-0454. Full text in Research Archive Show summary

  The European Union has introduced stricter provisions for medical devices under the new Medical Device Regulation (MDR). The MDR increases requirements for clinical trial testing for many devices before they can legally be placed on the market and extends requirements for rigorous clinical surveillance of benefits and harms to the entire life cycle of devices. New “expert panels” have been established by the European Commission to advise in the assessment of devices toward certification, and the role of previous “notified bodies” (private companies charged by the Commission with ensuring that manufacturers follow the requirements for device testing) is being expanded. The MDR does not contain a grandfathering clause; thus, all existing medical devices must be recertified under the stricter regulation. The recertification deadline has recently been extended to 2027 or 2028, depending on the device's risk class. Whether most device manufacturers can meet these new requirements is uncertain, and the MDR will likely have important consequences for manufacturers, researchers, clinicians, and patients. Enhanced collaborations between the medical device industry and physician partners will be needed to meet the new requirements in a timely manner to avoid shortages of existing devices and to mitigate barriers to development of new devices.

• Bretthauer, Michael & Kalager, Mette (2023). What is my risk, doctor? How to convey disease risk and treatment effects. The BMJ. doi: 10.1136/bmj-2022-075289. Full text in Research Archive
• Zeng, Linan; Helsingen, Lise Mørkved; Bretthauer, Michael; Agoritsas, Thomas; Vandvik, Per Olav & Mustafa, Reem A. [Show all 15 contributors for this article] (2023). A novel framework for incorporating patient values and preferences in making guideline recommendations: guideline panel surveys. Journal of Clinical Epidemiology. ISSN 0895-4356. doi: 10.1016/j.jclinepi.2023.07.003. Full text in Research Archive
• Langeland, Eline Aurvoll; Pisani, Synne E. R.; Kalager, Mette; Bretthauer, Michael & Helsingen, Lise Mørkved (2023). Følger Helsedirektoratets retningslinjer internasjonale standarder for troverdighet? Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 143(14). doi: 10.4045/tidsskr.23.0110. Full text in Research Archive Show summary

  BAKGRUNN - Helsedirektoratet produserer nasjonale faglige retningslinjer for helsetjenesten, og utviklingen av retningslinjene skal følge internasjonale standarder for troverdighet. Vi undersøkte om standardene blir fulgt.<p> <p>MATERIALE OG METODE - Vi benyttet skåringsverktøyet National Guideline Clearinghouse Extent of Adherence to Trustworthy Standards Instrument (NEATS), og vurderte ett tilfeldig valgt kapittel fra nasjonale faglige retningslinjer publisert eller oppdatert fra 2013 til januar 2022. NEATS har 15 domener: tre vurderes med svaralternativene ja/nei/ukjent, og tolv vurderes på en Likert-skala fra 1 til 5, der 1 tilsvarer svært lav troverdighet og 5 utmerket troverdighet. Vurderingene ble gjort individuelt av to forfattere. Interobservatørsamsvar ble vurdert med eksakt og nært samsvar samt Cohens kappa.<p> <p>RESULTATER - Vi inkluderte 60 gjeldende retningslinjer. For ni av tolv NEATS-domener vurdert med Likert-skala var det svært lav eller lav overholdelse av standarder for troverdige retningslinjer (median skår 1 eller 2). Domenene med lavest skår (median skår 1) var «studieseleksjon», «beskrivelse av studiene og resultatene», «gradering av styrken på anbefalingene» og «ekstern høring». Domenet med høyest skår var «spesifikk og utvetydig formulering av anbefalingene» (median skår 4).<p> <p>FORTOLKNING - Flertallet av de nasjonale faglige retningslinjene overholdt i liten grad standarder for troverdige retningslinjer vurdert med skåringsverktøyet NEATS.<p>

• Zeng, Linan; Li, Shelly-Anne; Yang, Mengting; Yan, Lijiao; Helsingen, Lise Mørkved & Bretthauer, Michael [Show all 15 contributors for this article] (2023). Qualitative study of guideline panelists: innovative surveys provided valuable insights regarding patient values and preferences. Journal of Clinical Epidemiology. ISSN 0895-4356. doi: 10.1016/j.jclinepi.2023.07.014. Full text in Research Archive
• Tønnesen, Christer Julseth; Hjelmesæth, Jøran Sture; Aabakken, Lars; Lund, Randi Størdal; Johnson, Line Kristin & Hertel, Jens Kristoffer [Show all 9 contributors for this article] (2023). A pilot study of implementation of endoscopic sleeve gastroplasty (ESG) in Norway. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 58(10), p. 1180–1184. doi: 10.1080/00365521.2023.2204389. Full text in Research Archive Show summary

  Bariatric surgery is the most effective treatment for obesity but is invasive and associated with serious complications. Endoscopic sleeve gastroplasty (ESG) is a less invasive weight loss procedure to reduce the stomach volume by full-thickness sutures. ESG has been adopted in many countries, but implementation at Scandinavian centres has not yet been documented. We performed a clinical pilot trial at a Norwegian centre with the primary objective to assess the feasibility of the ESG procedure. Patients and methods We included the first 10 patients treated with ESG at a Norwegian centre in a single-arm pilot study. The eligibility criteria were either a body mass index (BMI) of 40–49.9 kg/m2, BMI 35–39.9 kg/m2 and at least one obesity-related comorbidity, or BMI 30–34.9 kg/m2 and type 2 diabetes. Patient follow-up resembled the scheme used for bariatric surgery at the center, including dietary plans and outpatient visits. Results All procedures were technically successful except for one patient who had adhesions between the stomach and anterior abdominal wall, related to a prior hernia repair, resulting in less-than-intended stomach volume reduction. Mean total body weight loss (TBWL) after 26 and 52 weeks was 12.2% (95% CI 8.1–16.2) and 9.1% (95% CI 3.3 − 15.0). One patient experienced a minor suture-induced diaphragmatic injury, which was successfully managed conservatively. Conclusions This first Scandinavian clinical trial of ESG, documenting the implementation of the procedure at a Norwegian center, demonstrated acceptable feasibility and safety, with large variations in individual weight loss during the 52-week follow-up period.

• Hassan, Cesare; Piovani, Daniele; Spadaccini, Marco; Parigi, Tommaso; Khalaf, Kareem & Facciorusso, Antonio [Show all 14 contributors for this article] (2023). Variability in adenoma detection rate in control groups of randomized colonoscopy trials: a systematic review and meta-analysis. Gastrointestinal Endoscopy. ISSN 0016-5107. 97(2), p. 212–225.e7. doi: 10.1016/j.gie.2022.10.009. Full text in Research Archive
• Everett, Simon M.; Triantafyllou, Konstantinos; Hassan, Cesare; Mergener, Klaus; Tham, Tony C. & Almeida, Nuno [Show all 21 contributors for this article] (2023). Informed consent for endoscopic procedures: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement. Endoscopy. ISSN 0013-726X. 55(10), p. 952–966. doi: 10.1055/a-2133-3365. Full text in Research Archive
• Bretthauer, Michael; Wieszczy, Paulina; Løberg, Magnus; Kamiński, Michał Filip; Werner, Tarjei Fiskergård & Helsingen, Lise Mørkved [Show all 10 contributors for this article] (2023). Estimated Lifetime Gained with Cancer Screening Tests: A Meta-Analysis of Randomized Clinical Trials. JAMA Internal Medicine. ISSN 2168-6106. 183(11), p. 1196–1203. doi: 10.1001/jamainternmed.2023.3798. Full text in Research Archive
• Yu, Jingru; Refsum, Erle; Wieszczy, Paulina; Helsingen, Lise Mørkved; Perrin, Vera & Högdén, Amanda [Show all 12 contributors for this article] (2023). Risk of malignant lymphomas in patients with inflammatory bowel disease: a population-based cohort study. BMJ open gastroenterology. 10(1). doi: 10.1136/bmjgast-2022-001037. Full text in Research Archive
• Jodal, Henriette C.; Wieszczy, Paulina; Klotz, Dagmar; Herfindal, Magnhild; Barua, Ishita & Tag, Petter [Show all 13 contributors for this article] (2023). A Comparison of Risk Classification Systems of Colorectal Adenomas: A Case-Cohort Study. Gastroenterology. ISSN 0016-5085. 165, p. 483–491. doi: 10.1053/j.gastro.2023.04.028. Full text in Research Archive Show summary

  Background & Aims Because post-polypectomy surveillance uses a growing proportion of colonoscopy capacity, more targeted surveillance is warranted. We therefore compared surveillance burden and cancer detection using 3 different adenoma classification systems. Methods In a case-cohort study among individuals who had adenomas removed between 1993 and 2007, we included 675 individuals with colorectal cancer (cases) diagnosed a median of 5.6 years after adenoma removal and 906 randomly selected individuals (subcohort). We compared colorectal cancer incidence among high- and low-risk individuals defined according to the traditional (high-risk: diameter ≥10 mm, high-grade dysplasia, villous growth pattern, or 3 or more adenomas), European Society of Gastrointestinal Endoscopy (ESGE) 2020 (high-risk: diameter ≥10 mm, high-grade dysplasia, or 5 or more adenomas), and novel (high-risk: diameter ≥20 mm or high-grade dysplasia) classification systems. For the different classification systems, we calculated the number of individuals recommended frequent surveillance colonoscopy and estimated number of delayed cancer diagnoses. Results Four hundred and thirty individuals with adenomas (52.7%) were high risk based on the traditional classification, 369 (45.2%) were high risk based on the ESGE 2020 classification, and 220 (27.0%) were high risk based on the novel classification. Using the traditional, ESGE 2020, and novel classifications, the colorectal cancer incidences per 100,000 person-years were 479, 552, and 690 among high-risk individuals, and 123, 124, and 179 among low-risk individuals, respectively. Compared with the traditional classification, the number of individuals who needed frequent surveillance was reduced by 13.9% and 44.2%, respectively, and 1 (3.4%) and 7 (24.1%) cancer diagnoses were delayed using the ESGE 2020 and novel classifications. Conclusions Using the ESGE 2020 and novel risk classifications will substantially reduce resources needed for colonoscopy surveillance after adenoma removal.

• Spadaccini, Marco; Hassan, Cesare; Rondonotti, Emanuele; Antonelli, Giulio; Andrisani, Gianluca & Lollo, Gianluca [Show all 40 contributors for this article] (2023). Combination of Mucosa-Exposure Device and Computer-Aided Detection for Adenoma Detection During Colonoscopy: A Randomized Trial. Gastroenterology. ISSN 0016-5085. 165(1), p. 244–251. doi: 10.1053/j.gastro.2023.03.237. Full text in Research Archive
• Holme, Øyvind; Kalager, Mette; Bretthauer, Michael; Adami, Hans Olov; Helsingen, Lise Mørkved & Løberg, Magnus (2023). Ongoing Trials Will Not Determine the Comparative Effectiveness of Colorectal Cancer Screening Tests. Gastroenterology. ISSN 0016-5085. 164(6), p. 856–860. doi: 10.1053/j.gastro.2020.02.071. Full text in Research Archive
• Juul, Frederik Emil; Garborg, Kjetil Kjeldstad; Nesbakken, Philip Eugen; Løberg, Magnus; Wieszczy, Paulina & Cubiella, Joaquín [Show all 19 contributors for this article] (2022). Rates of repeated colonoscopies to clean the colon from low-risk and high-risk adenomas: Results from the EPoS trials. Gut. ISSN 0017-5749. doi: 10.1136/gutjnl-2022-327696. Full text in Research Archive Show summary

  Objective High-quality colonoscopy (adequate bowel preparation, whole-colon visualisation and removal of all neoplastic polyps) is a prerequisite to start polyp surveillance, and is ideally achieved in one colonoscopy. In a large multinational polyp surveillance trial, we aimed to investigate clinical practice variation in number of colonoscopies needed to enrol patients with low-risk and high-risk adenomas in polyp surveillance. Design We retrieved data of all patients with low-risk adenomas (one or two tubular adenomas <10 mm with low-grade dysplasia) and high-risk adenomas (3–10 adenomas, ≥1 adenoma ≥10 mm, high-grade dysplasia or villous components) in the European Polyp Surveillance trials fulfilling certain logistic and methodologic criteria. We analysed variations in number of colonoscopies needed to achieve high-quality colonoscopy and enter polyp surveillance by endoscopy centre, and by endoscopists who enrolled ≥30 patients. Results The study comprised 15 581 patients from 38 endoscopy centres in five European countries; 6794 patients had low-risk and 8787 had high-risk adenomas. 961 patients (6.2%, 95% CI 5.8% to 6.6%) underwent two or more colonoscopies before surveillance began; 101 (1.5%, 95% CI 1.2% to 1.8%) in the low-risk group and 860 (9.8%, 95% CI 9.2% to 10.4%) in the high-risk group. Main reasons were poor bowel preparation (21.3%) or incomplete colonoscopy/polypectomy (14.4%) or planned second procedure (27.8%). Need of repeat colonoscopy varied between study centres ranging from 0% to 11.8% in low-risk adenoma patients and from 0% to 63.9% in high-risk adenoma patients. On the second colonoscopy, the two most common reasons for a repeat (third) colonoscopy were piecemeal resection (26.5%) and unspecified reason (23.9%). Conclusion There is considerable practice variation in the number of colonoscopies performed to achieve complete polyp removal, indicating need for targeted quality improvement to reduce patient burden. Trial registration number NCT02319928.

• Barua, Ishita; Misawa, Masashi; Brown, Jeremy R. Glissen; Walradt, Trent; Kudo, Shin-ei & Sheth, Sunil G. [Show all 19 contributors for this article] (2022). Speedometer for withdrawal time monitoring during colonoscopy: a clinical implementation trial. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2022.2154616. Full text in Research Archive
• Mori, Yuichi; Misawa, Masashi; Bernal, Jorge; Bretthauer, Michael; Kudo, Shin-ei & Rastogi, Amit [Show all 7 contributors for this article] (2022). Artificial intelligence for disease diagnosis: the criterion standard challenge. Gastrointestinal Endoscopy. ISSN 0016-5107. 96(2), p. 370–372. doi: 10.1016/j.gie.2022.04.057. Full text in Research Archive
• Yu, Jingru; Refsum, Erle; Perrin, Vera; Helsingen, Lise Mørkved; Wieszczy, Paulina & Løberg, Magnus [Show all 11 contributors for this article] (2022). Inflammatory bowel disease and risk of adenocarcinoma and neuroendocrine tumors in the small bowel. Annals of Oncology. ISSN 0923-7534. p. 1–8. doi: 10.1016/j.annonc.2022.02.226. Full text in Research Archive
• Burra, Patrizia; Arvanitakis, Marianna; Dias, Jorge Amil; Bretthauer, Michael; Dugic, Ana & Hartmann, Daniel [Show all 13 contributors for this article] (2022). UEG position paper: Obesity and digestive health. United European Gastroenterology Journal (UEG Journal). ISSN 2050-6406. doi: 10.1002/ueg2.12334. Full text in Research Archive
• Barua, Ishita; Wieszczy, Paulina; Kudo, Shin-ei; Masashi, Misawa; Holme, Øyvind & Gulati, Shraddha [Show all 34 contributors for this article] (2022). Real-Time Artificial Intelligence–Based Optical Diagnosis of Neoplastic Polyps during Colonoscopy. NEJM Evidence. 1(6). doi: 10.1056/EVIDoa2200003. Full text in Research Archive
• Ainechi, Diba; Misawa, Masashi; Barua, Ishita; Larsen, Solveig; Paulsen, Vemund & Garborg, Kjetil Kjeldstad [Show all 21 contributors for this article] (2022). Impact of artificial intelligence on colorectal polyp detection for early-career endoscopists: an international comparative study. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. doi: 10.1080/00365521.2022.2070436. Full text in Research Archive Show summary

  Background Artificial intelligence (AI) for polyp detection is being introduced to colonoscopy, but there is uncertainty how this affects endoscopists’ ability to detect polyps and neoplasms. We performed a video-based study to address whether AI improved the endoscopists’ performance to detect polyps. Methods We established a dataset of 200 colonoscopy videos (length 5 s; 100 without polyps and 100 with one polyp). About 33 early-career endoscopists (50–400 colonoscopies performed) from 10 European countries classified each video as either ‘polyp present’ or ‘polyp not present’. The video assessment was performed twice with a four-week interval. The first assessment was performed without any AI tool, whereas the second was performed with an AI tool for polyp detection. The primary endpoint was early-career endoscopists’ sensitivity to detect polyps. Gold standard for presence and histology of polyps were confirmed by two expert endoscopists and pathologists, respectively. McNemar’s test was used for statistical significance. Results There were 86 neoplastic and 14 non-neoplastic polyps (mean size 5.6 mm) in the 100 videos with polyps. Early-career endoscopists’ sensitivity to detect polyps increased from 86.3% (95% confidence interval [CI]: 85.1–87.5%) to 91.7% (95%CI: 90.7–92.6%) with the AI aid (p < .0001). Their sensitivity to detect neoplastic polyps increased from 85.4% (95% CI: 84.0–86.7%) to 92.1% (95%CI: 91.1–93.1%) with the AI aid (p < .0001). Conclusion The polyp detection AI tool helped early-career endoscopists to increase their sensitivity to identify all polyps and neoplastic polyps during colonoscopy.

• Juul, Frederik Emil; Cross, Amanda J.; Schoen, Robert E.; Senore, Carlo; Pinsky, Paul & Miller, Eric [Show all 17 contributors for this article] (2022). 15-Year Benefits of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality : A Pooled Analysis of Randomized Trials. Annals of Internal Medicine. ISSN 0003-4819. 175(11), p. 1525–1533. doi: 10.7326/M22-0835. Full text in Research Archive Show summary

  Background: The effectiveness of screening for colorectal cancer (CRC) by sex and age in randomized trials is uncertain. Objective: To evaluate the 15-year effect of sigmoidoscopy screening on CRC incidence and mortality. Design: Pooled analysis of 4 large-scale randomized trials of sigmoidoscopy screening. Setting: Norway, the United States, the United Kingdom, and Italy. Participants: Women and men aged 55 to 64 years at enrollment. Intervention: Sigmoidoscopy screening. Measurements: Primary end points were cumulative incidence rate ratio (IRR) and mortality rate ratio (MRR) and rate differences after 15 years of follow-up comparing screening versus usual care in intention-to-treat analyses. Stratified analyses were done by sex, cancer site, and age at screening. Results: Analyses comprised 274 952 persons (50.7% women), 137 493 in the screening and 137 459 in the usual care group. Screening attendance was 58% to 84%. After 15 years, the rate difference for CRC incidence was 0.51 cases (95% CI, 0.40 to 0.63 cases) per 100 persons and the IRR was 0.79 (CI, 0.75 to 0.83). The rate difference for CRC mortality was 0.13 deaths (CI, 0.07 to 0.19 deaths) per 100 persons, and the MRR was 0.80 (CI, 0.72 to 0.88). Women had less benefit from screening than men for CRC incidence (IRR for women, 0.84 [CI, 0.77 to 0.91]; IRR for men, 0.75 [CI, 0.70 to 0.81]; P = 0.032 for difference) and mortality (MRR for women, 0.91 [CI, 0.77 to 1.17]; MRR for men, 0.73 [CI, 0.64 to 0.83]; P = 0.025 for difference). There was no statistically significant difference in screening effect between persons aged 55 to 59 years and those aged 60 to 64 years. Limitation: Data from the U.K. trial were less granular because of privacy regulations. Conclusion: This pooled analysis of all large randomized trials of sigmoidoscopy screening demonstrates a significant and sustained effect of sigmoidoscopy on CRC incidence and mortality for 15 years.

• Baile-Maxia, Sandra; Mangas-Sanjuan, Carolina; Ladabaum, Uri; Hassan, Cecare; Rutter, Matthew D. & Bretthauer, Michael [Show all 11 contributors for this article] (2022). Risk Factors for Metachronous Colorectal Cancer or Advanced Adenomas After Endoscopic Resection of High-risk Adenomas. Clinical Gastroenterology and Hepatology. ISSN 1542-3565. 21(3), p. 630–643. doi: 10.1016/j.cgh.2022.12.005. Full text in Research Archive
• Areia, Miguel; Mori, Yuichi; Correale, Loredana; Repici, Alessandro; Bretthauer, Michael & Sharma, Prateek [Show all 18 contributors for this article] (2022). Cost-effectiveness of artificial intelligence for screening colonoscopy: a modelling study. The Lancet Digital Health. 4(6), p. e436–e444. doi: 10.1016/S2589-7500(22)00042-5. Full text in Research Archive Show summary

  Background Artificial intelligence (AI) tools increase detection of precancerous polyps during colonoscopy and might contribute to long-term colorectal cancer prevention. The aim of the study was to investigate the incremental effect of the implementation of AI detection tools in screening colonoscopy on colorectal cancer incidence and mortality, and the cost-effectiveness of such tools. Methods We conducted Markov model microsimulation of using colonoscopy with and without AI for colorectal cancer screening for individuals at average risk (no personal or family history of colorectal cancer, adenomas, inflammatory bowel disease, or hereditary colorectal cancer syndrome). We ran the microsimulation in a hypothetical cohort of 100 000 individuals in the USA aged 50–100 years. The primary analysis investigated screening colonoscopy with versus without AI every 10 years starting at age 50 years and finishing at age 80 years, with follow-up until age 100 years, assuming 60% screening population uptake. In secondary analyses, we modelled once-in-life screening colonoscopy at age 65 years in adults aged 50–79 years at average risk for colorectal cancer. Post-polypectomy surveillance followed the simplified current guideline. Costs of AI tools and cost for downstream treatment of screening detected disease were estimated with 3% annual discount rates. The main outcome measures included the incremental effect of AI-assisted colonoscopy versus standard (no-AI) colonoscopy on colorectal cancer incidence and mortality, and cost-effectiveness of screening projected for the average risk screening US population. Findings In the primary analyses, compared with no screening, the relative reduction of colorectal cancer incidence with screening colonoscopy without AI tools was 44·2% and with screening colonoscopy with AI tools was 48·9% (4·8% incremental gain). Compared with no screening, the relative reduction in colorectal cancer mortality with screening colonoscopy with no AI was 48·7% and with screening colonoscopy with AI was 52·3% (3·6% incremental gain). AI detection tools decreased the discounted costs per screened individual from $3400 to $3343 (a saving of $57 per individual). Results were similar in the secondary analyses modelling once-in-life colonoscopy. At the US population level, the implementation of AI detection during screening colonoscopy resulted in yearly additional prevention of 7194 colorectal cancer cases and 2089 related deaths, and a yearly saving of US$290 million. Interpretation Our findings suggest that implementation of AI detection tools in screening colonoscopy is a cost-saving strategy to further prevent colorectal cancer incidence and mortality. Funding European Commission and Japan Society of Promotion of Science.

• Ichimasa, Katsuro; Nakahara, Kenta; Kudo, Shin-ei; Misawa, Masashi; Bretthauer, Michael & Shimada, Shoji [Show all 14 contributors for this article] (2022). Novel “resect and analysis” approach for T2 colorectal cancer with use of artificial intelligence. Gastrointestinal Endoscopy. ISSN 0016-5107. 96(4), p. 665–672.e1. doi: 10.1016/j.gie.2022.04.1305. Full text in Research Archive
• Santiago, Enrique Rodríguez De; Dinis-Ribeiro, Mario; Pohl, Heiko; Agrawal, Deepak; Arvanitakis, Marianna & Baddeley, Robin [Show all 33 contributors for this article] (2022). Reducing the environmental footprint of gastrointestinal endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastroenterology and Endoscopy Nurses and Associates (ESGENA) Position Statement. Endoscopy. ISSN 0013-726X. 54(8), p. 797–826. doi: 10.1055/a-1859-3726. Full text in Research Archive
• Barua, Ishita; Bretthauer, Michael & Mori, Yuichi (2022). Computer-aided quality assessment (CAQ): the next step for artificial intelligence in colonoscopy? Mini-invasive Surgery. 6. doi: 10.20517/2574-1225.2022.05. Full text in Research Archive
• Yu, Jingru; Refsum, Erle; Helsingen, Lise Mørkved; Folseraas, Trine; Ploner, Alexander & Wieszczy, Paulina [Show all 15 contributors for this article] (2022). Risk of hepato-pancreato-biliary cancer is increased by primary sclerosing cholangitis in patients with inflammatory bowel disease: A population-based cohort study. United European Gastroenterology Journal (UEG Journal). ISSN 2050-6406. 10(2), p. 212–224. doi: 10.1002/ueg2.12204. Full text in Research Archive Show summary

  Background There is continued uncertainty regarding the risks of hepato-pancreato-biliary cancers in patients with inflammatory bowel disease (IBD) with or without concomitant primary sclerosing cholangitis (PSC). Objective To give updated estimates on risk of hepato-pancreato-biliary cancers in patients with IBD, including pancreatic cancer, hepatocellular carcinoma, gall bladder cancer, and intra – and extrahepatic cholangiocarcinoma. Methods In a population-based cohort study, we included all patients diagnosed with IBD in Norway and Sweden from 1987 to 2016. The cohort comprised of 141,960 patients, identified through hospital databases and the National Patient Register. Participants were followed through linkage to national cancer, cause of death, and population registries. We calculated absolute risk and standardized incidence ratios (SIRs) of hepato-pancreato-biliary cancers by PSC and other clinical characteristics. Results Of the 141,960 IBD patients, 3.2% were diagnosed with PSC. During a median follow-up of 10.0 years, we identified 443 biliary tract cancers (SIR 5.2, 95% confidence interval [CI] 4.8–5.7), 161 hepatocellular carcinomas (SIR 2.4, 95% CI 2.0–2.7) and 282 pancreatic cancers (SIR 1.3, 95% CI 1.2–1.5). The relative risks were considerably higher in PSC-IBD patients, with SIR of 140 (95% CI 123–159) for biliary tract, 38.6 (95% CI 29.2–50.0) for hepatocellular, and 9.0 (95% CI 6.3–12.6) for pancreatic cancer. The SIRs were still slightly increased in non-PSC-IBD patients, compared to the general population. For biliary tract cancer, the cumulative probability at 25 years was 15.6% in PSC-IBD patients, and 0.4% in non-PSC-IBD patients. Conclusions The dramatically increased risks of hepato-pancreato-biliary cancers in PSC-IBD patients support periodic surveillance for these malignancies. While much lower, the excess relative risks in non-PSC-IBD patients were not trivial compared to non-IBD related risk factors.

• Mori, Yuichi; Wang, Pu; Løberg, Magnus; Misawa, Masashi; Repici, Alessandro & Spadaccini, Marco [Show all 26 contributors for this article] (2022). Impact of Artificial Intelligence on Colonoscopy Surveillance After Polyp Removal: A Pooled Analysis of Randomized Trials. Clinical Gastroenterology and Hepatology. ISSN 1542-3565. doi: 10.1016/j.cgh.2022.08.022. Full text in Research Archive Show summary

  Background and Aims Artificial intelligence (AI) tools aimed at improving polyp detection have been shown to increase the adenoma detection rate during colonoscopy. However, it is unknown how increased polyp detection rates by AI affect the burden of patient surveillance after polyp removal. Methods We conducted a pooled analysis of 9 randomized controlled trials (5 in China, 2 in Italy, 1 in Japan, and 1 in the United States) comparing colonoscopy with or without AI detection aids. The primary outcome was the proportion of patients recommended to undergo intensive surveillance (ie, 3-year interval). We analyzed intervals for AI and non-AI colonoscopies for the U.S. and European recommendations separately. We estimated proportions by calculating relative risks using the Mantel-Haenszel method. Results A total of 5796 patients (51% male, mean 53 years of age) were included; 2894 underwent AI-assisted colonoscopy and 2902 non-AI colonoscopy. When following U.S. guidelines, the proportion of patients recommended intensive surveillance increased from 8.4% (95% CI, 7.4%–9.5%) in the non-AI group to 11.3% (95% CI, 10.2%–12.6%) in the AI group (absolute difference, 2.9% [95% CI, 1.4%–4.4%]; risk ratio, 1.35 [95% CI, 1.16–1.57]). When following European guidelines, it increased from 6.1% (95% CI, 5.3%–7.0%) to 7.4% (95% CI, 6.5%–8.4%) (absolute difference, 1.3% [95% CI, 0.01%–2.6%]; risk ratio, 1.22 [95% CI, 1.01–1.47]). Conclusions The use of AI during colonoscopy increased the proportion of patients requiring intensive colonoscopy surveillance by approximately 35% in the United States and 20% in Europe (absolute increases of 2.9% and 1.3%, respectively). While this may contribute to improved cancer prevention, it significantly adds patient burden and healthcare costs.

• Jodal, Henriette C.; Juul, Frederik Emil; Barua, Ishita; Bretthauer, Michael; Kalager, Mette & Løberg, Magnus [Show all 7 contributors for this article] (2022). Emergency hospital admissions, prognosis, and population mortality in Norway during the first wave of the Covid-19 epidemic. Scandinavian Journal of Public Health. ISSN 1403-4948. 50(6), p. 795–802. doi: 10.1177/14034948221082959. Full text in Research Archive Show summary

  Background: During the first wave of the Covid-19 epidemic, a national lockdown was established in Norway, and inhabitants were asked to contact healthcare only if absolutely necessary. We investigated hospital admissions and mortality due to non-Covid-19 disease during the lockdown compared to previous years. Methods: We compared the number of emergency admissions and in-hospital fatality for diagnoses probably unaffected (acute myocardial infarction, acute abdominal conditions, cerebrovascular diseases) and affected by the lockdown (infections, injuries) in the South-Eastern Health Region of Norway during weeks 12–22, 2020, compared to the mean of the same period in the years 2017–2019. We also compared population mortality March–May 2020, to the mean of the same period in years 2017–2019. Results: A total of 280,043 emergency admissions were observed; 20,911 admissions probably unaffected, and 30,905 admissions probably affected by the lockdown. Admissions due to diagnoses probably unaffected was reduced by 12% (95% confidence interval (CI) 9–15%), compared to 2017–2019. Admissions for diagnoses probably affected was reduced by 30% (95% CI 28–32%). There was a 34% reduction in in-hospital fatality due to acute myocardial infarction (95% CI 4–56%), 19% due to infections (95% CI 1–33%), and no change for the other diagnoses, compared to 2017–2019. The risk of in-hospital mortality to total mortality was lower for acute myocardial infarction (relative risk 0.85, 95% CI 0.73–0.99) and injuries (relative risk 0.83, 95% CI 0.70–0.98). Conclusions: Even though fewer patients were admitted to hospital, there was no increase in in-hospital fatality or population mortality, indicating that those who were most in need still received adequate care.

• Pedersen, Ina Borgenheim; Rawa-Goleblewska, Anna; Calderwood, Audrey H.; Brix, Lone D.; Grode, Louise B. & Botteri, Edoardo [Show all 17 contributors for this article] (2022). Complete Polyp Resection with Cold versus Hot snare Polypectomy for Polyps sized 4-9 mm: A randomized controlled trial. Endoscopy. ISSN 0013-726X. 54(10), p. 961–969. doi: 10.1055/a-1734-7952. Full text in Research Archive Show summary

  Background: Endoscopic screening with polypectomy reduces the incidence of colorectal cancer (CRC). Incomplete polyp removal may attenuate the effect of screening. This randomized trial compared cold snare polypectomy (CSP) with hot snare polypectomy (HSP) in terms of complete polyp resection. Methods: We included patients ≥ 40 years of age at eight hospitals in four countries who had at least one non-pedunculated polyp of 4-9 mm detected at colonoscopy. Patients were randomized 1:1 to CSP or HSP. Biopsies from the resection margins were obtained systematically after polypectomy in both groups. We hypothesized that CSP would be non-inferior to HSP, with a non-inferiority margin of 5 %. Logistic regression models were fitted to identify the factors explaining incomplete resection. Results: 425 patients, with 601 polyps, randomized to either CSP or HSP were included in the analysis. Of 318 polyps removed by CSP and 283 polyps removed by HSP, 34 (10.7 %) and 21 (7.4 %) were incompletely resected, respectively, with an adjusted risk difference of 3.2 % (95 %CI -1.4 % to 7.8 %). There was no difference between the groups in terms of post-polypectomy bleeding, perforation, or abdominal pain. Independent risk factors for incomplete removal were serrated histology (odds ratio [OR] 3.96; 95 %CI 1.63 to 9.66) and hyperplastic histology (OR 2.52; 95 %CI 1.30 to 4.86) in adjusted analyses. Conclusion: In this randomized trial, non-inferiority for CSP could not be demonstrated. Polyps with serrated histology are more prone to incomplete resection compared with adenomas. CSP can be used safely for small polyps in routine colonoscopy practice.

• Bretthauer, Michael; Løberg, Magnus; Wieszczy, Paulina; Kalager, Mette; Emilsson, Louise & Garborg, Kjetil Kjeldstad [Show all 21 contributors for this article] (2022). Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death. New England Journal of Medicine. ISSN 0028-4793. 387(17), p. 1547–1556. doi: 10.1056/NEJMoa2208375. Full text in Research Archive Show summary

  Background: Although colonoscopy is widely used as a screening test to detect colorectal cancer, its effect on the risks of colorectal cancer and related death is unclear. Methods: We performed a pragmatic, randomized trial involving presumptively healthy men and women 55 to 64 years of age drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio to either receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the usual-care group). The primary end points were the risks of colorectal cancer and related death, and the secondary end point was death from any cause. Results: Follow-up data were available for 84,585 participants in Poland, Norway, and Sweden - 28,220 in the invited group, 11,843 of whom (42.0%) underwent screening, and 56,365 in the usual-care group. A total of 15 participants had major bleeding after polyp removal. No perforations or screening-related deaths occurred within 30 days after colonoscopy. During a median follow-up of 10 years, 259 cases of colorectal cancer were diagnosed in the invited group as compared with 622 cases in the usual-care group. In intention-to-screen analyses, the risk of colorectal cancer at 10 years was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio, 0.82; 95% confidence interval [CI], 0.70 to 0.93). The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16). The number needed to invite to undergo screening to prevent one case of colorectal cancer was 455 (95% CI, 270 to 1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (risk ratio, 0.99; 95% CI, 0.96 to 1.04). Conclusions: In this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening. (Funded by the Research Council of Norway and others; NordICC ClinicalTrials.gov number, NCT00883792.).

• Waldmann, Elisabeth; Kammerlander, Andreas A.; Gessl, Irina; Penz, Daniela; Majcher, Barbara & Hinterberger, Anna [Show all 9 contributors for this article] (2021). Association of Adenoma Detection Rate and Adenoma Characteristics With Colorectal Cancer Mortality After Screening Colonoscopy. Clinical Gastroenterology and Hepatology. ISSN 1542-3565. 19(9), p. 1890–1898. doi: 10.1016/j.cgh.2021.04.023. Full text in Research Archive
• Usher-Smith, Juliet A.; Mills, Katie M.; Riedinger, Christiane; Saunders, Catherine L.; Helsingen, Lise Mørkved & Lytvyn, Lyubov [Show all 11 contributors for this article] (2021). The impact of information about different absolute benefits and harms on intention to participate in colorectal cancer screening: A think-aloud study and online randomised experiment. PLOS ONE. 16(2). doi: 10.1371/journal.pone.0246991. Full text in Research Archive
• Schult, Anna Lisa; Botteri, Edoardo; Hoff, Geir; Holme, Øyvind; Bretthauer, Michael & Randel, Kristin Ranheim [Show all 13 contributors for this article] (2021). Women require routine opioids to prevent painful colonoscopies: a randomised controlled trial. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 56(12), p. 1480–1489. doi: 10.1080/00365521.2021.1969683. Full text in Research Archive Show summary

  Background: Women are at high risk for painful colonoscopy. Pain, but also sedation, are barriers to colorectal cancer (CRC) screening participation. In a randomised controlled trial, we compared on-demand with pre-colonoscopy opioid administration to control pain in women at CRC screening age. Methods: Women, aged 55-79 years, attending colonoscopy at two Norwegian endoscopy units were randomised 1:1:1 to (1) fentanyl on-demand, (2) fentanyl prior to colonoscopy, or (3) alfentanil on-demand. The primary endpoint was procedural pain reported by the patients on a validated four-point Likert scale and further dichotomized for the study into painful (moderate or severe pain) and non-painful (slight or no pain) colonoscopy. Secondary endpoints were: willingness to repeat colonoscopy, adverse events, cecal intubation time and rate, and post-procedure recovery time. Results: Between June 2017 and May 2020, 183 patients were included in intention-to-treat analyses in the fentanyl on-demand group, 177 in the fentanyl prior to colonoscopy group, and 179 in the alfentanil on-demand group. Fewer women receiving fentanyl prior to colonoscopy reported a painful colonoscopy compared to those who were given fentanyl on-demand (25.2% vs. 44.1%, p

• Mori, Yuichi; Bretthauer, Michael & Kalager, Mette (2021). Hopes and Hypes for Artificial Intelligence in Colorectal Cancer Screening. Gastroenterology. ISSN 0016-5085. 161(3), p. 774–777. doi: 10.1053/j.gastro.2021.04.078. Full text in Research Archive
• Jodal, Henriette C.; Klotz, Dagmar; Herfindal, Magnhild; Barua, Ishita; Tag, Petter & Helsingen, Lise Mørkved [Show all 12 contributors for this article] (2021). Long-term colorectal cancer incidence and mortality after adenoma removal in women and men. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. p. 1–10. doi: 10.1111/apt.16686. Full text in Research Archive
• Mori, Yuichi; Neumann, Helmut; Misawa, Masashi; Kudo, Shin-Ei & Bretthauer, Michael (2021). Artificial intelligence in colonoscopy - Now on the market. What's next? Journal of Gastroenterology and Hepatology. ISSN 0815-9319. 36, p. 7–11. doi: 10.1111/jgh.15339. Full text in Research Archive
• Juul, Frederik E.; Jodal, Henriette C.; Barua, Ishita; Refsum, Erle; Olsvik, Ørjan & Helsingen, Lise Mørkved [Show all 10 contributors for this article] (2021). Mortality in Norway and Sweden during the COVID-19 pandemic. Scandinavian Journal of Public Health. ISSN 1403-4948. p. 1–8. doi: 10.1177/14034948211047137. Full text in Research Archive Show summary

  Background: Norway and Sweden are similar countries in terms of socioeconomics and health care. Norway implemented extensive COVID-19 measures, such as school closures and lockdowns, whereas Sweden did not. Aims: To compare mortality in Norway and Sweden, two similar countries with very different mitigation measures against COVID-19. <p> <p>Methods: Using real-world data from national registries, we compared all-cause and COVID-19-related mortality rates with 95% confidence intervals (CI) per 100,000 person-weeks and mortality rate ratios (MRR) comparing the five preceding years (2015–2019) with the pandemic year (2020) in Norway and Sweden. <p> <p>Results: In Norway, all-cause mortality was stable from 2015 to 2019 (mortality rate 14.6–15.1 per 100,000 person-weeks; mean mortality rate 14.9) and was lower in 2020 than from 2015 to 2019 (mortality rate 14.4; MRR 0.97; 95% CI 0.96–0.98). In Sweden, all-cause mortality was stable from 2015 to 2018 (mortality rate 17.0–17.8; mean mortality rate 17.1) and similar to that in 2020 (mortality rate 17.6), but lower in 2019 (mortality rate 16.2). Compared with the years 2015–2019, all-cause mortality in the pandemic year was 3% higher due to the lower rate in 2019 (MRR 1.03; 95% CI 1.02–1.04). Excess mortality was confined to people aged ⩾70 years in Sweden compared with previous years. The COVID-19-associated mortality rates per 100,000 person-weeks during the first wave of the pandemic were 0.3 in Norway and 2.9 in Sweden. <p> <p>Conclusions: All-cause mortality in 2020 decreased in Norway and increased in Sweden compared with previous years. The observed excess deaths in Sweden during the pandemic may, in part, be explained by mortality displacement due to the low all-cause mortality in the previous year.

• Tønnesen, Christer Julseth; Hjelmesæth, Jøran; Hofsø, Dag; Tonstad, Serena; Hertel, Jens Kristoffer & Heggen, Eli [Show all 14 contributors for this article] (2021). A novel intragastric balloon for treatment of obesity and type 2 diabetes. A two-center pilot trial. Scandinavian Journal of Gastroenterology. ISSN 0036-5521. 57(2), p. 232–238. doi: 10.1080/00365521.2021.1994641. Full text in Research Archive Show summary

  Background and aims: Obesity with type-2 diabetes is a global challenge. Lifestyle interventions have limited effect for most patients. Bariatric surgery is highly effective, but resource-demanding, invasive and associated with serious complications. Recently, a new intragastric balloon was introduced, not requiring endoscopy for placement or removal (Elipse™, Allurion Inc., Natick, MA). The balloon is swallowed in a capsule and filled with water once in the stomach. The balloon self-deflates after 4 months and is naturally excreted. The present trial investigated balloon feasibility, safety and efficacy in patients with obesity and type-2 diabetes. <p> <p>Patients and methods: We treated 19 patients, with type-2 diabetes and body mass index (BMI) of 30.0-39.9 kg/m2 at two Norwegian centers with the Elipse balloon. Patient follow-up during balloon treatment mimicked real-world clinical practice, including dietary plan and outpatient visits. The primary efficacy endpoints were total body weight loss (TBWL) and HbA1c at weeks 16 and 52. <p> <p>Results: All patients underwent balloon insertion uneventfully as out-patients. Mean TBWL and HbA1c reduction after 16 and 52 weeks of balloon insertion was 3.9% (95%CI 2.1-5.7) and 0.8% (95%CI 1.9-3.5); and 7 (95%CI 4-10), and 1 (95%CI -6 to 9) mmol/mol, respectively. Adverse events occurred in two patients (10.5%): one developed gastric outlet obstruction, managed by endoscopic balloon removal; the other excessive vomiting and dehydration, managed conservatively. <p> <p>Conclusions: This first Scandinavian real-world clinical trial with a new minimally invasive intragastric balloon system demonstrated good feasibility, but did not confirm expected efficacy for weight loss and diabetes control.

• Wieszczy, Paulina; Kaminski, Michal F; Løberg, Magnus; Bugajski, Marek; Bretthauer, Michael & Kalager, Mette (2021). Estimation of overdiagnosis in colorectal cancer screening with sigmoidoscopy and faecal occult blood testing: Comparison of simulation models. BMJ Open. 11(4), p. 1–10. doi: 10.1136/bmjopen-2020-042158. Full text in Research Archive

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• Kalager, Mette; Bretthauer, Michael; Graver, Hans Petter; Helsingen, Lise Mørkved; Løberg, Magnus & Nylund, Anna [Show all 7 contributors for this article] (2025). Forholdsmessighet. Medisin, juss, filosofi og pandemi. Fagbokforlaget. ISBN 9788245053555. 348 p. Full text in Research Archive

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• Weinberg, David S. & Bretthauer, Michael (2026). Upskilling, Deskilling, or Never Skilling: Who Benefits From Artificial Intelligence in Colonoscopy? Gastroenterology. ISSN 0016-5085. doi: 10.1053/j.gastro.2026.05.026. Full text in Research Archive
• Weinberg, David & Bretthauer, Michael (2025). Screening for mange krefttyper med én blodprøve – for godt til å være sant? doi: 10.4045/tidsskr.25.0077. Full text in Research Archive
• Bretthauer, Michael & Gjersvik, Petter (2025). Stepwise Wedge Cluster Randomization. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 145(8). doi: 10.4045/tidsskr.25.0094. Full text in Research Archive
• Bø, Sebastian; Wiig, Håvard; Juul, Frederik Emil; Garborg, Kjetil Kjeldstad; Johnsen, Peter Holger & Bretthauer, Michael (2025). Tarmflorabehandling mot førstegangsinfeksjon med Clostridioides difficile. doi: 10.4045/tidsskr.25.0276. Full text in Research Archive
• Cintosun, Amber; Jamal, Imran; Samnani, Sunil; Song, Yi Nong & Bretthauer, Michael (2025). Gastroenterology/Hepatology: What You May Have Missed in 2024. Annals of Internal Medicine. ISSN 0003-4819. 178(5), p. S39–S53. doi: 10.7326/ANNALS-25-00959. Full text in Research Archive
• Bretthauer, Michael (2024). Pasientjournaler og nasjonale kvalitetsregistre – to sider av samme sak. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(14), p. 1–4. doi: 10.4045/tidsskr.24.0525. Full text in Research Archive
• Helsingen, Lise Mørkved; Langeland, Eline Aurvoll; Pisani, Synne Eline Rotihaug; Vandvik, Per Olav; Haavardsholm, Espen A. & Malt, Ulrik Fredrik [Show all 10 contributors for this article] (2024). Glansbilder av nasjonale faglige retningslinjer fra Helsedirektoratet. Tidsskrift for Den norske legeforening (Tidsskriftet). ISSN 0029-2001. 144(5). doi: 10.4045/tidsskr.24.0141. Full text in Research Archive
• Bretthauer, Michael (2024). How to learn from interval cancers in colorectal cancer screening. Endoscopy. ISSN 0013-726X. doi: 10.1055/a-2279-9932. Full text in Research Archive
• Nordberg, Lena Bugge; Pohl, Heiko; Haavardsholm, Espen A.; Lillegraven, Siri & Bretthauer, Michael (2024). Carbon-Footprint Analyses in RCTs — Toward Sustainable Clinical Practice. 390(24), p. 2234–2236. doi: 10.1056/NEJMp2402018. Full text in Research Archive
• Juul, Frederik Emil; Bretthauer, Michael; Tonby, Kristian; Berdal, Jan-Erik; Hoff, Dag Arne Lihaug & Ofstad, Eirik Hugaas [Show all 27 contributors for this article] (2024). Fecal microbiota transplant versus Vancomycin for primary Clostridioides difficile infection - a randomized non-inferiority trial. Full text in Research Archive
• Bretthauer, Michael; Kaminski, Michal F. & Kalager, Mette (2024). Lifetime Gained with Cancer Screening - Reply. JAMA Internal Medicine. ISSN 2168-6106. doi: 10.1001/jamainternmed.2023.7067. Full text in Research Archive
• Song, Mingyang & Bretthauer, Michael (2024). Authors’ Reply: Interpreting epidemiologic studies of colonoscopy screening for colorectal cancer prevention. European Journal of Epidemiology (EJE). ISSN 0393-2990. doi: 10.1007/s10654-023-01077-2. Full text in Research Archive
• Bretthauer, Michael & Ponchon, Thierry (2024). ESGE and Public Advocacy. Endoscopy. ISSN 0013-726X. 56(6), p. 457–458. doi: 10.1055/a-2277-2204. Full text in Research Archive
• Bretthauer, Michael; Mori, Yuichi; Zessner-Spitzenberg, Jasmin; Kamiński, Michał F.; Siersema, Peter D. & Ponchon, Thierry [Show all 10 contributors for this article] (2023). Gastrointestinal endoscopy devices and the European Union Medical Device Regulation: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement. Endoscopy. ISSN 0013-726X. 55(6), p. 578–581. doi: 10.1055/a-2052-2540. Full text in Research Archive
• Song, Mingyang & Bretthauer, Michael (2023). Authors’ Reply: Interpreting epidemiologic studies of colorectal cancer prevention. European Journal of Epidemiology (EJE). ISSN 0393-2990. doi: 10.1007/s10654-023-01070-9. Full text in Research Archive
• Hanley, James A.; Deck, Wilber; Winawer, Sidney J.; Hoffmeister, Michael; Cardoso, Rafael & Brenner, Hermann [Show all 14 contributors for this article] (2023). Colonoscopy Screening and Colorectal Cancer Incidence and Mortality. New England Journal of Medicine. ISSN 0028-4793. 388(4), p. 376–379. doi: 10.1056/NEJMc2215192. Full text in Research Archive
• Jodal, Henriette C.; Bretthauer, Michael & Løberg, Magnus (2023). Tarmkreftscreening også for yngre? 143(18), p. 1–5. doi: 10.4045/tidsskr.23.0553. Full text in Research Archive
• Bretthauer, Michael & Yang, Yu-Xiao (2023). New American College of Physicians Guidance on Colorectal Cancer Screening: Less Is More. Annals of Internal Medicine. ISSN 0003-4819. 176(8), p. 1127–1128. doi: 10.7326/M23-1695. Full text in Research Archive
• Gantzel, Rasmus; Wieszczy, Paulina; Refsum, Erle; Jess, Tine; Larsen, Lone & Bretthauer, Michael [Show all 11 contributors for this article] (2023). Prognostic models for colorectal cancer incidence and mortality in patients with inflammatory bowel disease. Cochrane Database of Systematic Reviews. doi: 10.1002/14651858.CD015434. Full text in Research Archive
• Øverenget, Einar; Kalager, Mette; Grødeland, Gunnveig; Olsvik, Ørjan; Nylund, Anna & Løberg, Magnus [Show all 8 contributors for this article] (2022). Når smittevern blir uforståelig. Full text in Research Archive
• Bretthauer, Michael; Schoen, Robert E.; Cross, Amanda J. & Pinsky, Paul F. (2022). Colorectal Cancer Screening: Randomized Trials Are Essential to Support Recommendations. Annals of Internal Medicine. ISSN 0003-4819. 175(1), p. 129–130. doi: 10.7326/M21-3770. Full text in Research Archive
• Jodal, Henriette C.; Bretthauer, Michael; Kalager, Mette & Løberg, Magnus (2022). Letter: long-term colorectal cancer incidence and mortality after adenoma removal associated with heritable factors, colonoscopic surveillance and aspirin—authors' reply. Alimentary Pharmacology and Therapeutics. ISSN 0269-2813. 55(10), p. 1363–1364. doi: 10.1111/apt.16929. Full text in Research Archive
• Helsingen, Lise Mørkved; Løberg, Magnus; Bretthauer, Michael & Kalager, Mette (2022). Reply to: Letter to the Editor regarding "Covid-19 transmission in fitness centers in Norway-a randomized trial". BMC Public Health. 22(1), p. 2437–2437. doi: 10.1186/s12889-022-14799-x. Full text in Research Archive
• Mori, Yuichi; Kamiński, Michał Filip; Hassan, Cecare & Bretthauer, Michael (2022). Clinical trial designs for artificial intelligence in gastrointestinal endoscopy. The Lancet Gastroenterology and Hepatology. ISSN 2468-1253. doi: 10.1016/S2468-1253(22)00232-1. Full text in Research Archive
• Gralnek, Ian; Hassan, Cesare; Ebigbo, Alanna; Fuchs, Andre; Beilenhoff, Ulrike & Antonelli, Giulio [Show all 27 contributors for this article] (2021). ESGE and ESGENA Position Statement on gastrointestinal endoscopy and COVID-19: Updated guidance for the era of vaccines and viral variants. doi: 10.1055/a-1700-4897. Full text in Research Archive
• Bretthauer, Michael; Kalager, Mette & Weinberg, David S. (2021). Colorectal cancer screening in young adults: About carcinoid tumors and cancer. Annals of Internal Medicine. ISSN 0003-4819. 174(2), p. 263–265. doi: 10.7326/M20-7244. Full text in Research Archive
• Mori, Yuichi & Bretthauer, Michael (2021). Addressing false-positive findings with artificial intelligence for polyp detection. Endoscopy. ISSN 0013-726X. 53(9), p. 941–942. doi: 10.1055/a-1381-7849. Full text in Research Archive
• Bretthauer, Michael; Løberg, Magnus; Holme, Øyvind; Adami, Hans-Olov & Kalager, Mette (2021). Deep learning and cancer biomarkers: recognising lead-time bias. The Lancet. ISSN 0140-6736. 397(10270), p. 194–194. doi: 10.1016/S0140-6736(20)32402-8. Full text in Research Archive

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