Colon to Rectum
N Engl J Med. 2022;387(17):1547–56
Effect of colonoscopy screening on risks of colorectal cancer and related death
Background: Although colonoscopy is widely used as a screening test to detect colorectal cancer (CRC), its effect on the risks of CRC and related death is unclear.
Methods: The authors performed a pragmatic, randomized trial involving presumptively healthy men and women 55 to 64 years of age drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio either to receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the usual-care group). The primary end points were the risks of CRC and related death, and the secondary end point was death from any cause.
Results: Follow-up data were available for 84,585 participants in Poland, Norway, and Sweden: 28,220 in the invited group, 11,843 of whom (42.0%) underwent screening, and 56,365 in the usual-care group. A total of 15 participants had major bleeding after polyp removal. No perforations or screening-related deaths occurred within 30 days after colonoscopy. During a median follow-up of 10 years, 259 cases of CRC were diagnosed in the invited group as compared with 622 cases in the usual-care group. In intention-to-screen analyses, the risk of CRC at 10 years was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio [RR] = 0.82; 95% confidence interval [CI]: 0.70–0.93). The risk of death from CRC was 0.28% in the invited group and 0.31% in the usual-care group (RR = 0.90; 95% CI: 0.64–1.16). The number needed to invite to undergo screening to prevent 1 case of CRC was 455 (95% CI: 270–1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (RR = 0.99; 95% CI: 0.96–1.04).
Conclusions: In this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening.