Initially developed in Japan for the treatment of endemic superficial gastric cancers, endoscopic submucosal dissection (ESD) allows resection of pre-neoplastic and neoplastic lesions of the digestive tract into a single fragment. It allows a perfect pathological analysis, and decreases the rate of recurrence of the adenoma to less than 2% However, this procedure, which is technically more challenging, is also more risky (perforation rate at 4% vs. 1% for WF-EMR) and longer. Submucosal dissection is also more expensive in terms of equipment, but this difference can be offset by the cost of the high number of iterative colonoscopies required in patients who have had endoscopic resection by WF-EMR.

Scientific debate is agitating the Western world1,2 and Japanese experts do not perform WF-EMR anymore, whereas no comparative prospective study has compared these two procedures.

We therefore propose to compare these two endoscopic resection strategies in terms of recurrence rate at 6 months and to estimate the differential cost-effectiveness and cost-utility ratios over a 36-month time horizon.

Inclusion Criteria:

• Patient suffering from non-pedunculated polyp suspected larger than 25 mm in the colon
• Colon localization beyond 15 cm of the anal margin.
• Indication for endoscopic treatment
• Patients aged ≥ 18 years old
• Patients able to fill in questionnaires written in French

Exclusion Criteria:

• Prior endoscopic resection attempt
• Contra-indication to colonoscopy
• Contra-indication to general anesthesia
• Inability to stop antiplatelet agents and anti-coagulant according to the European Society of Gastro-Intestinal Endoscopy guidelines.
• Recurrent adenoma: post-endoscopic or surgical resection
• Pregnant or lactating women
• Genetic polyposis (Familial Adenomatous Polyposis, Lynch Syndrome, Peutz-Jeghers Syndrome)
• Inability to provide informed consent
• Patient under legal protection and or deprived of liberty by judicial or administrative decision
• Patient already participating in an interventional clinical research protocol
• Patient who cannot be followed for the duration of the study
• Non-pedunculated polyp ≤ 25 mm
• More than one lesion > 25 mm that fulfilled the inclusion criteria
• Suspicion of deep submucosal cancer by analysis of macroscopic appearance (Paris 0-III), vascular pattern and pit pattern (SANO IIIB, KUDO Vn)
• Non granular pseudodepressed Laterally spreading tumors due to the high risk of nonvisible submucosal cancer
• Polyp involving the appendice deeply (type 2 or 3 of classification of Toyonaga)
• Polyp inside the ileo-caecal valvula
• Tattoing under the lesion
• Inflammatory Bowel Disease with expected fibrosis (Crohn disease or ulcerative colitis)
• Colon localization < 15 cm of the anal margin.
• Polyp invading a diverticulum
• Pedunculated polyp
• Absence of lesion