Digital Public Defence: Anna Lisa Schult

MD Anna Lisa Schult at Institute of Clinical Medicine will be defending the thesis “Performance of two screening tests and barriers to colorectal cancer screening” for the degree of PhD (Philosophiae Doctor).

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Photo: Therese Talmø-Rønn, The Cancer Registry of Norway

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

Download Zoom here

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

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Adjudication committee

  • First opponent: Senior Consultant Roland Valori, Glouchestershire Royal Hospital, UK
  • Second opponent: Researcher Anna Forsberg, Karolinska Institutet, Sweden
  • Third member and chair of the evaluation committee: Associate Professor Marte Lie Høivik, University of Oslo

Chair of the Defence

Professor II Arnljot Tveit, University of Oslo

Principal Supervisor

 Professor Thomas de Lange, University of Oslo


Colorectal cancer (CRC) is a major health burden. Screening can reduce both incidence and mortality of CRC. Endoscopic screening with sigmoidoscopy or colonoscopy and testing for occult blood in stool are the most frequently applied methods, but the comparative effectiveness is unknown. Effectiveness of screening depends on the test used, but also on high participation in screening. Anticipation of pain can jeopardize participation in endoscopic screening programmes. Women have a higher risk of painful colonoscopies than men. The absence of bowel symptoms may be another barrier to screening participation, as asymptomatic individuals show a lower adherence to screening programmes.

The present thesis is based on data from a Norwegian randomised CRC screening trial. About 140.000 individuals were invited to either sigmoidoscopy or repeated faecal immunochemical tests (FIT).

The results showed that the participation rate in FIT screening was higher than in sigmoidoscopy screening. More CRCs and advanced adenomas were detected at FIT screening and most of the neoplasia were detected in asymptomatic screening participants. Women receiving analgesia prior to colonoscopy reported fewer painful colonoscopies than women treated with analgesia on-demand.

The comparative effectiveness of sigmoidoscopy and FIT screening is unknown until results from long-term follow-up are available. Nevertheless, the present thesis provides important information about planning and implementing a colorectal cancer screening programme. The results highlight the importance of encouraging asymptomatic individuals to participate in screening programmes. It was also shown that analgesia should be offered to women before colonoscopy starts. Optimized pain relief during colonoscopy may have impact on the reputation of screening and thus increase participation rates and effectiveness of endoscopic screening.

Additional information

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Published Mar. 3, 2022 10:08 PM - Last modified Mar. 30, 2022 1:24 PM