The public defence will be held as a video conference over Zoom.
The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.
Click here to participate in the public defence
Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.
Digital Trial Lecture - time and place
Adjudication committee
- First opponent: Associate Professor Asmaa Shaukat, University of Minnesota, USA
- Second opponent: Professor Berit Andersen, Aarhus University, Denmark
- Third member and chair of the evaluation committee: Professor Kristian Bjøro, Institute of Clinical Medicine, University of Oslo
Chair of defence
Professor II Lars Aabakken, Institute of Clinical Medicine, University of Oslo
Principal Supervisor
Associate Professor Øyvind Holme, Institute of Health and Society, University of Oslo
Summary
Colorectal cancer (CRC) is a major health burden and among the most common cancers worldwide. Screening reduces CRC mortality and can reduce CRC incidence by removal of possible precursors, e.g. adenomas. Both endoscopic examination and faecal testing are among available screening methods. There is, however, limited evidence on which is the best strategy.
This thesis reports from a large randomised CRC screening trial in Norway. About 140,000 individuals aged 50-74 years were invited to either one-time sigmoidoscopy or repeated faecal immunochemical testing (FIT). Colonoscopy was offered in case of a positive screening test. The aim of the thesis was to compare attendance, findings at time of screening, and adverse events between the two screening methods. The thesis also explores findings at different threshold values for FIT positivity and among screen-positive participants on antithrombotic treatment.
The results showed higher attendance and detection of CRC and advanced adenoma, but less non-advanced adenomas, after three FIT rounds compared to one-time sigmoidoscopy screening. The rates of perforation and significant bleeding were as expected, and did not differ between the two groups. If increasing the FIT threshold to levels used in some European countries, less colonoscopies would be needed, but substantially less advanced adenomas and cancers would be detected. Use of direct-acting oral anticoagulants and aspirin were associated with lower positive predictive values for cancer and advanced adenoma among FIT positive participants.
The results presented in this thesis provide important knowledge both in the planning of a national CRC screening program in Norway, and for decision-makers in countries where programs are imminent or already ongoing.
Additional information
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