Endoscopic full-thickness resection (EFTR) in the colon using an over-the-scope clip (OTSC) as a closure mechanism is a recent technique that allows the endoscopic resection of colonic lesions that are poor candidates for conventional endoscopic resection techniques. The aim is to study the safety and efficacy of EFTR in colon.

Early detection and endoscopic resection of early neoplastic lesions in colon can prevent the development of colon cancer.

The classic endoscopic mucosal resection technique and the submucosal dissection technique require the creation of a submucosal "cushion" by injecting crystalloid substances or colloids. However, these advanced techniques have technical limitations when facing a lesion that presents poor lifting or non-lifting at all as it might be observed in scarring or fibrotic lesions

Endoscopic full-thickness resection (EFTR) in the colon using an over-the-scope clip (OTSC) is a recent technique that does not require the injection of a submucosal solution and allows a resection of colonic lesions of up to approximately 30 mm, en bloc, allowing a correct histological study of the sample, to confirm its complete resection with adequate deep margins, evaluation of the level of invasion and lymphovascular involvement.

EFTR with OTSC allows a colonic wall full-thickness resection, by the deployment of an over-the-scope clip before the resection of the lesion to prevent perforation. The steps of the technique are: face the lesion and marking the borders, insertion of the scope with the kit (consisting of a cap with an integrated snare and OTSC), grasping and pulling the lesion into the cap, deploy the over-the-scope-clip (OTSC) and closing the integrated snare and resect.

This is a multicenter observational study on the efficacy and safety of EFTR with OTSC in colon.

The clinical, endoscopic and histological data are collected prospectively in all cases of EFTR performed in the participant centers.

Inclusion Criteria:

• Adults (≥18 years) of both sexes.
• Colonic lesions less than 30mm unresectable en-bloc by other less invasive endoscopic techniques, including lesions suggestive of T1, subepithelial tumors, lesions with diverticular involvement, lesions with no-lifting signs (recurrent, incomplete prior resection or untreated).
• Patients who give their written informed consent for the procedure and for the study.

Exclusion Criteria:

• Refusal to grant informed consent.
• Neoplastic lesions of the colon with evidence of advanced stage (for example, lymph node involvement) or more than 3 cm in greatest diameter.
• Any medical, psychological, geographical, or social problem that is significant and uncontrolled that may interfere with the patient's participation in the study or that does not allow adequate follow-up and adherence to the protocol and evaluation of the results of the study.

All patients who undergo a endoscopic full-thickness resection for colonic lesions who meet the inclusion criteria will be included consecutively.