Twenty-Three–Year Benefits of Sigmoidoscopy Screening for Colorectal Cancer
Mené en Norvège auprès de 98 654 personnes âgées de 50 à 64 ans, cet essai randomisé évalue l'effet, sur l'incidence du cancer colorectal et le risque de décès sur une période de 23 ans, d'un dépistage par sigmoïdoscopie en combinaison ou non avec un test FIT
Background : Meta-analyses of randomized trials have shown that sigmoidoscopy screening reduces colorectal cancer (CRC) incidence and death for 15 years.
Objective : To report the benefits of sigmoidoscopy after 23 years.
Design : Randomized controlled trial. (NORCCAP [Norwegian Colorectal Cancer Prevention], ClinicalTrials.gov: NCT00119912)
Setting : Population of Oslo and Telemark County, Norway.
Participants : Persons aged 50 to 64 years without CRC at randomization.
Intervention : Screening with once-only sigmoidoscopy, with or without 1 fecal immunochemical test, or no screening.
Measurements : Colorectal cancer incidence and death.
Results : A total of 100 210 persons were randomly assigned, and 98 654 were included in intention-to-screen analyses: 20 552 in the screening group and 78 102 in the no-screening group. Participation with screening was 61.4% in men and 64.7% in women. In men, the 23-year cumulative risk for CRC was 4.3% in the screening group and 6.0% in the no-screening group, corresponding to a risk difference of
−
1.7 percentage points (95% CI,
−
2.2 to
−
1.2 percentage points). In women, the corresponding risks were 4.2% and 4.7%, yielding a risk difference of
−
0.5 percentage points (CI,
−
1.0 to
−
0.01 percentage points). In men, the 23-year cumulative risk for CRC death was 1.4% in the screening group and 2.2% in the no-screening group, corresponding to a risk difference of
−
0.8 percentage points (CI,
−
1.1 to
−
0.5 percentage points). In women, the corresponding risks were 1.3% and 1.4%, yielding a risk difference of
−
0.1 percentage points (CI,
−
0.3 to 0.1 percentage points). The effect was strongest for rectosigmoid cancer. The addition of fecal blood testing to sigmoidoscopy did not change screening benefits.
Limitation : Follow-up through national registries.
Conclusion : Offering sigmoidoscopy screening in Norway reduced CRC incidence more in men than in women and reduced CRC death only in men.
Primary Funding Source : Norwegian government and Norwegian Cancer Society.
Annals of Internal Medicine , article en libre accès, 2026