A randomized study on colorectal cancer screening (NORCCAP)

NORCCAP (Norwegian Colorectal Cancer Prevention) is a randomized study on screening for colorectal cancer (CRC) and adenomatous polyps (potential precursor lesions for colorectal cancer).
Last updated: 2/11/2021


The NORCCAP project is a randomized study on screening for, and prevention of, colorectal cancer (CRC). NORCCAP was also a pilot on a possible national screening program. The project was initiated by the Norwegian Gastrointestinal Cancer Group (NGICG) and the Norwegian Cancer Society with shared funding between the Norwegian Cancer Society and the Ministry of Health and Care Services. The Cancer Registry took over the ownership of NORCCAP in 2002. The study was started and carried out under the leadership of Geir Hoff.

The screening examinations were carried out over the course of three years (1999-2001) in Oslo and Telemark. 21,000 women and men aged 50-64, living in Oslo and Telemark, were randomly drawn from the population registry and offered a screening examination by flexible sigmoidoscopy (flexible endoscope for examination of the distal 50-60 cm of the large intestine). The rest of the population in this age range (n=79,000) constituted the control group. Half of the invitees were asked to deliver a stool sample for supplementary screening for blood in the feces (FOB-testing with an immunochemical test – FlexSure OBT®) and for research purposes to develop new stool-based screening methods. In line with this, blood samples were also taken. Participants have been followed over time.



So far, 64 original articles and 12 Ph.D theses have been published. Much of the research done has been of great value also to routine clinical activity. The quality assurance program in NORCCAP-I has developed further into a separate programme - Gastronet – a network for quality development in gastrointestinal endoscopy in Norway. Gastronet has become one of the national quality assurance programs of the Norwegian Directorate of Health and the official quality assurance platform for the Norwegian Gastroenterology Society.


Selected publications

Rounge TBMeisal RNordby JIAmbur OHde Lange THoff G (2018)
Evaluating gut microbiota profiles from archived fecal samples
BMC Gastroenterol18 (1)171
DOI 10.1186/s12876-018-0896-6PubMed 30409123

Frozen stool samples stored for up to 16 years have sufficient microbial DNA-profiles to be used in studies on possible association between microbiota and the risk of bowel cancer.The study suggests that we may proceed with studies on stored stool samples to explore associations between microbiota and bowel cancer risk. No immediate transfer value to clinical work.

Holme ØLøberg MKalager MBretthauer MHernán MAAas EEide TJSkovlund ELekven JSchneede JTveit KMVatn MUrsin GHoff GNORCCAP Study Group† (2018)
Long-Term Effectiveness of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality in Women and Men: A Randomized Trial
Ann Intern Med168 (11)775-782
DOI 10.7326/M17-1441PubMed 29710125

The present study uses data from four large screening studies, including the Norwegian NORCCAP study, to develop alternative terms - the terms «number of adenomas needed to remove» (NNR) and «adenoma dwell time avoided» (DTA). DTA is similar to NNR, but incorporates also «time after removal of adenoma».

Holme ØBretthauer MEide TJLøberg EMGrzyb KLøberg MKalager MAdami HOKjellevold ØHoff G (2014). Long-term risk of colorectal cancer in individuals with serrated polyps. Gut64 (6)929-36. DOI PubMed 25399542

The previously shown effects of flexible sigmoidoscopy screening in other studies also holds true for an unselected average risk population. Flexible sigmoidoscopy screening is at present the only CRC screening method shown to reduce CRC incidence, not only CRC mortality. The results are better than those shown in studies on fecal occult blood screening. Transfer value to national screening programmes.

Berstad PLøberg MLarsen IKKalager MHolme ØBotteri EBretthauer MHoff G(2014). Long-term lifestyle changes after colorectal cancer screening: randomised controlled trial. Gut64 (8)1268-76. PubMed 25183203

During the last year of active screening in the NORCCAP trial (2001), 13,961 individuals in the screening and the control groups were asked to fill in a questionnaire on lifestyle. This was repeated in 2004 and 2012. The proportion adhering to international recommendations on lifestyle improved with time for both groups, but the improvement in lifestyle was weaker in the screening group, particularly among those having identified (and removed) polyps at screening.



All NORCCAP publications