An interventional study of A 1 Intervention arm Flex Sig and A 2 Intervention arm Flex Sig + iFOBT in Colorectal Cancer and Adenoma, sponsored by Norwegian Institute of Public Health. Active, not recruiting at 1 site in Norway. Open to participants aged 50 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-14.
Sponsored by Norwegian Institute of Public Health · Not applicable, Interventional, and Prevention
The purpose of this study is to see if screening with flexible sigmoidoscopy (a flexible viewing tube) may reduce large bowel cancer and cancer deaths. The researchers also want to see if the addition of screening for occult blood in stools may contribute further to this aim. Additionally, the researchers also want to see to which extent (and in which direction) the study may influence overall endoscopic activity in the general population in the screening area and in areas where controlled screening is not established.
Although flexible sigmoidoscopy (FS) as a screening tool has a much higher test sensitivity than fecal occult blood tests (FOBT) for colorectal cancer and high-risk adenomas, randomised trials with long-term follow-up are missing. The primary aim is to evaluate the effect on CRC mortality and morbidity by screen detection of CRC and removal of precursor lesions (polypectomy of adenomatous polyps)
Secondary aims:
Population:
21,000 men and women, aged 50-64 years, living in the city of Oslo or the county of Telemark are drawn by randomisation (approx. 1:5) from the population registry and invited to have a flexible sigmoidoscopy examination. The control group constitutes 79,000 individuals. Those invited for flexible sigmoidoscopy are further randomised (1:1) to bring or not to bring 3 successive stool samples for FOBT on attendance for FS.
Method:
This is a once-only screening concept with bowel cleansing being limited to a 240 ml Sorbitol enema given on attendance. The threshold for work-up colonoscopy is low as a positive screening test is defined as any polyp >9mm, any histologically verified adenoma irrespective of size and a positive FOBT. The screening phase is limited to the period January 1999- January 2002 and the first follow-up results will not be reported until all entries have passed the 5-year mark (i.e. in early 2007).
5,600 studies on the registry are indexed under Colorectal Neoplasms; 1,459 are open to participants now.
This study's enrollment of 100,000 is above the median of 77 across 4,123 interventional studies indexed under Colorectal Neoplasms.
Browse Colorectal Neoplasms studies →Norwegian Institute of Public Health is the lead sponsor of 49 studies on the registry; 10 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Randomised from the population registry, age 50-64 years and invited for Flexible Sigmoidoscopy (Flex Sig) screening. Half of invitees are additionally invited to provide a stool sample for fecal occult blood testing (Intervention arm A 2). They are drawn directly from the population registry without prior consent to be randomized - approved by Regional Ethics Committees of South-East Norway..
Procedure: A 1 Intervention arm Flex Sig
"No screening group" randomised from population age 50-64 years. As for the active intervention arm, the control group was not informed about being randomized to 'no screening' since 'no screening' was the current usual care (and still is in 2015) in Norway - approved by Regional Ethics Committees of South-East Norway.
Randomised from the population registry, age 50-64 years and invited for Flexible Sigmoidoscopy (Flex Sig) screening plus an immunochemical test for fecal occult blood (iFOBT). As for arms A 1 and B, they are drawn directly from the population registry without prior consent to be randomized.
Procedure: A 2 Intervention arm Flex Sig + iFOBT
Screening by flexible sigmoidoscopy
In addition to Flexible Sigmoidoscopy, half of arm A (randomised 1:1) is invited to provide stool samples for FOBT
1. Evaluate the effect on CRC mortality and morbidity by screen detection of CRC and removal of precursor lesions (polypectomy of adenomatous polyps).First evaluation after 5 years.
CRC incidence and mortality is followed
Time frame: Evaluations in 2007 (published),2012,2017
1. Determine the prevalence of known types familial CRC in a general population and try to define other groups with intermediate increased risk. Results "in press" 2005.
Determine the prevalence of familial CRC in a general population sample
Time frame: Evaluated in 2005 (published)
2. Clarify possible psychosocial effects of endoscopic screening and how it may influence lifestyle and lifestyle related morbidity and overall mortality. Evaluation in 2005.
Determine psychosocial effects of invitation to screening and of screening findings
Time frame: Evaluated in 2005 (published)
This study is active, not recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Norwegian Institute of Public Health