ONE colonoscopy significantly reduced colorectal cancer incidence but not mortality over 13 years, in updated findings from an ongoing randomised controlled trial.1
In the population-based trial, 84,583 men and women, aged 55 to 64-years-old, from Norway, Poland, and Sweden, were allocated to colonoscopy or no-screening groups.
Results After 13 Years of Follow-Up
After 13 years, colorectal cancer incidence was 375 cancers of 28,217 people in the screening group (1.46%).
In the no-screening group, incidence was 912 colorectal cancers of 56,366 participants (1.80%).
Screening appeared to cut distal colorectal cancer incidence more than proximal colorectal cancer incidence.
In men, the colorectal cancer risk was 214 of 14,154 participants in the screening group (1.69%) and 541 of 28,247 people in the no-screening group (2.19%). 0.5
Alternatively, observed differences in incidence in women were significantly smaller.
Of 14,063 women in the screening group, the colorectal cancer risk was 161 (1.24%).
In the no screening group, the risk was 371 of 28,119 participants (1.43%).
In contrast to incidence, one colonoscopy did not significantly reduce colorectal cancer mortality, which was 0.41% in the screening group and 0.47% in the no-screening group – substantially lower than the 0.82% mortality rate expected at the time of designing the trial.
Colonoscopy as the Gold Standard
Colonoscopy has been promoted as the gold standard for colorectal cancer screening for more than two decades.2
Policy makers and professional societies have largely accepted observational and modelling estimates suggesting that colonoscopy cuts colorectal cancer incidence and mortality by at least 50%.3
In accompanying commentary, Aasma Shaukat, NYU Grossman School of Medicine, New York, USA, said: “The study’s 13-year results compel a recalibration of what colonoscopy can – and cannot – achieve at the population level.”2
References
1 Kaminski MF et al. Long-term effects of colonoscopy screening on colorectal cancer incidence and mortality: a multicountry, population-based randomised controlled trial. Lancet. 2026;407(10541):1787–1795.
2 Shaukat A. Colonoscopy, cancer prevention, and the new arithmetic of benefit. Lancet. 2026;407(10541):1758–1759.
3 US Preventive Services Task Force. Screening for colorectal cancer: US preventive services task force recommendation statement. JAMA. 2021;325:1965–1977.
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