Colorectal cancer (CRC) can be prevented by colonoscopy and polypectomy. Endoscopic mucosal resection (EMR) is performed to remove large laterally spreading colonic lesions, which have a high risk of progression to CRC. Endoscopically invisible micro-adenomas at the margins of the EMR site might contribute to adenoma recurrence, which occurs in 15%–30% of patients who undergo surveillance. We aimed to determine the efficacy of adjuvant thermal ablation of the EMR mucosal defect margin in reducing polyp recurrence.