Effect of colonoscopy on colorectal cancer, mortality risks

Editor's Note

This Norwegian study finds a lower risk of colorectal cancer at 10 years in those who had screening colonoscopy, compared to those with no screening.

Of 84,585 participants, 28,220 were invited to have a single screening colonoscopy (11,843 underwent screening), and 56,365 were in the usual care group. A total of 15 had major bleeding after polyp removal.

During a median follow-up of 10 years, 259 cases of colorectal cancer were diagnosed in the invited group vs 622 cases in the usual-care group, for a risk of 0.98% in the invited group and 1.20% in the usual care group—a risk reduction of 18%.

The death from colorectal cancer risk was 0.28% in the invited group and 0.31% in the usual-care group for a risk ratio of 0.90. The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual care group for a risk ratio of 0.99.

The results may serve to quantify the effectiveness of screening colonoscopy for the prevention of colorectal cancer and enable decision makers to prioritize resources for cancer screening and healthcare services, the researchers say.