Trial Finds Single Colonoscopy Lowers CRC Incidence but Not Mortality
A large randomized controlled trial with 13 years of follow-up found that a single screening colonoscopy significantly reduced colorectal cancer incidence but did not significantly reduce colorectal cancer mortality.
The multicountry study enrolled 84,583 adults aged 55 to 64 years from Norway, Poland, and Sweden. Participants were randomly assigned to undergo colonoscopy screening or receive no screening. Investigators evaluated colorectal cancer incidence and mortality after 10 to 15 years of follow-up.
At 13 years, colorectal cancer developed in 375 of 28,217 individuals (1.46%) in the screening group compared with 912 of 56,366 individuals (1.80%) in the no-screening group. In intention-to-screen analyses, colonoscopy was associated with a 19% reduction in colorectal cancer incidence (risk ratio [RR], 0.81; 95% CI, 0.71–0.90). In per-protocol analyses, the reduction was greater (RR, 0.55; 95% CI, 0.33–0.81).
The reduction in cancer incidence was more pronounced for distal colorectal cancers than proximal tumors. The risk of distal colorectal cancer was 0.87% in the screening group versus 1.11% in the no-screening group (RR, 0.79; 95% CI, 0.65–0.89), whereas the risk of proximal colorectal cancer was similar between groups (RR, 0.91; 95% CI, 0.71–1.09).
Differences were also observed by sex. Men experienced a greater reduction in colorectal cancer risk than women, with risk ratios of 0.77 and 0.87, respectively.
Colorectal cancer mortality was 0.41% in the screening group and 0.47% in the no-screening group. The intention-to-screen mortality risk ratio was 0.88 (95% CI, 0.68–1.08).
Investigators noted that “one colonoscopy significantly reduced colorectal cancer incidence but not mortality over 13 years.” They also observed that “colorectal cancer mortality was lower in both study groups than when the trial was designed.”
Reference
Kaminski M, Kalager M, Løberg M et al. Long-term effects of colonoscopy screening on colorectal cancer incidence and mortality: a multicountry, population-based randomised controlled trial. The Lancet, 2026; 407, 1787-1795.
