Randomized noninferiority trial of association of colononoscopy intervals with colorectal cancer incidence after adenoma removal

The optimal interval of colonoscopy surveillance after polyp removal is not clear. In the ongoing noninferiority EPoS II trial, in eight European countries, patients with high-risk adenomas (defined as ≥ 1 adenoma with a diameter of ≥ 10 mm, high-grade dysplasia, or villous growth or 3 to 10 adenomas of any kind) were randomized to undergo a first colonoscopy at 5 years (n=5398) or at 3 years (currently recommended in guidelines; n=5401). The 3-year group also underwent colonoscopy at 5 years. The primary endpoint was the cumulative incidence of colorectal cancer (CRC) at 10 years, with a noninferiority margin of 0.7 percentage points for the upper boundary of the confidence interval for the difference between the two groups. Results of an interim analysis after 5.5 years of follow-up have now been published. The 5-year cumulative incidence of CRC was 0.77% with less-frequent surveillance and 0.82% with more-frequent surveillance, meeting the criterion for noninferiority. The distribution of cancer stage at diagnosis did not appear to differ substantially between the two groups. Three patients (0.06%) in the 5-year group and two patients (0.04%) in the 3-year group died of CRC. The authors conclude that in this interim analysis, beginning surveillance colonoscopy at 5 years was noninferior to beginning at 3 years with respect to cumulative incidence of CRC at 5 years among patients with high-risk adenomas (quick take).