Relationship between frequency of surveillance colonoscopy and colorectal cancer prevention

Background and Aim The impact of frequent colonoscopy on colorectal cancer (CRC) remains unclear. The present study aimed to determine the relationship between frequency of surveillance colonoscopy and CRC prevention. Methods From April 2010 to April 2011, patients who underwent surveillance colonoscopy after screening and polypectomy in four Japanese endoscopy centers were enrolled in this multicenter historical cohort study. Patients were classified into the following two groups according to the findings of past colonoscopy: a low-risk group (no neoplasia or 1–2 cumulative adenomas