Prospective multicenter study of persistent recurrence rate and the optimal observation time after endoscopic piecemeal mucosal resection for colorectal neoplaisa

Interventions: interval of colonoscopy examination is 3 month
interval of colonoscopy examination is 6 month
Primary outcome(s): The comparison of each of the local recurrence rate during follow-up in 3 months and in six months after endoscopic piecemeal mucosal resection
Study Design: Parallel Randomized