Risk of Advanced Colorectal Neoplasia According to the Number of High-Risk Findings at Index Colonoscopy: A Korean Association for the Study of Intestinal Disease (KASID) Study

Background: Data regarding outcomes for patients with multiple findings for high-risk adenomas are scarce. Aim: To compare the risk for colorectal neoplasm (CRN) recurrence according to the number of high-risk findings. Methods: This was a retrospective and multicenter study. Patients who had one or more high-risk adenomas at the index colonoscopy and underwent follow-up colonoscopy 2.5 or more years after the index colonoscopy were included. The number of high-risk findings was defined as follows: number of adenomas larger than 1 cm + number of adenomas with HGD + number of adenomas with a villous component + existence (counted as 1) or nonexistence (counted as 0) of three or more adenomas. Results: A total of 1646 patients were included, and the mean duration between index and follow-up colonoscopy was approximately 4 years. The cumulative incidence rate of recurrent advanced CRN in patients with three or more high-risk findings was higher than that in patients with one or two high-risk findings (p < 0.001). However, the difference in 3-year cumulative incidence rates of recurrent advanced CRN between the two groups was not great, although it was statistically significant (4.8 vs. 2.3 %, p = 0.039). Conclusions: A 3-year surveillance interval for patients with multiple high-risk findings, regardless of the number of high-risk findings, appears reasonable.