Thermal Ablation of Mucosal Defect Margins Reduces Adenoma Recurrence After Colonic Endoscopic Mucosal Resection

Abstract

Background & Aims: Colorectal cancer (CRC) can be prevented by colonoscopy and polypectomy. Endoscopic mucosal resection (EMR) is performed to remove large laterally spreading colonic lesions that 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% to 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. Methods: We performed a prospective study of 390 patients with large laterally spreading colonic lesions (≥ 20 mm, n = 416) referred for EMR at 4 tertiary centers in Australia. After complete lesion excision by EMR, lesions were randomly assigned to thermal ablation of the post-EMR mucosal defect margin (n = 210) or no additional treatment (controls, n = 206). We performed surveillance colonoscopies with standardized photo documentation and biopsies of the scar after 5 to 6 months. Patient, procedure, and lesion characteristics were similar between the groups. The primary endpoint was detection of lesion recurrence at first surveillance colonoscopy. Results: A significantly lower proportion of patients who received thermal ablation of the post-EMR mucosal defect margin had evidence of recurrence at first surveillance colonoscopy (10/192, 5.2%) than controls (37/176, 21.0%) (P