Public Defence: Cassia Bree Trewin-Nybråten

M.Sc. Cassia Bree Trewin-Nybråten at Institute of Clinical Medicine will be defending the thesis “Changing socioeconomic patterns of breast cancer incidence, mortality and survival in Norway” for the degree of PhD (Philosophiae Doctor).

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Photo: Elisabeth Jakobsen,

Cancer Registry of Norway

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Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Professor Susanne Oksbjerg Dalton, Danish Cancer Society Research Center, Denmark
  • Second opponent: Senior Lecturer Mark Clements, Karolinska Institutet, Sweden
  • Third member and chair of the evaluation committee: Associate Professor Cecilie Dahl, University of Oslo

Chair of the Defence

Professor Tone Kristin Omsland, University of Oslo

Principal Supervisor

Director, Professor II Giske Ursin, Cancer Registry of Norway, University of Oslo

Summary

Breast cancer has had a reversed socioeconomic gradient compared to most diseases. For decades, women with a high socioeconomic status have had the highest risk of being diagnosed with breast cancer and dying from breast cancer.

However, since the new millennium, socioeconomic patterns for breast cancer incidence and mortality seem to be changing.

To better understand these changing patterns, this thesis aimed to describe socioeconomic differences over time in breast cancer incidence, mortality and survival in Norway. Three epidemiological studies were performed using individually-linked Norwegian registry data covering the entire female population of Norway.

Breast cancer incidence and mortality trends were analysed with Poisson models, whereas breast cancer survival trends were analysed with flexible parametric models.

These analyses revealed a changing socioeconomic pattern for breast cancer in Norway favouring women with a high socioeconomic status.

Women with high socioeconomic status have had a more modest increase in breast cancer incidence, and greater decline in breast cancer mortality over time, compared to women with low socioeconomic status, in particular for young women below age 50 years.

Since the new millennium, young women with a low socioeconomic status are still less often diagnosed with breast cancer but now die more often from breast cancer than young women with a high socioeconomic status.

Late detection does not seem to play a role, but other factors relating to prognosis after diagnosis seem to explain the higher breast cancer mortality for young women with low socioeconomic status.

Even in a country with universal health care, socioeconomic factors such as education and income level seem to play a role for breast cancer outcomes.

Additional information

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Published Jan. 27, 2023 11:34 AM - Last modified Feb. 8, 2023 2:19 PM