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

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 (>= 20mm, 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 defectmargin (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 patientswho received thermal ablation of the post-EMRmucosal defect margin had evidence of recurrence at first surveillance colonoscopy (10/192, 5.2%) than controls (37/176, 21.0%) (P < .001). The relative risk of recurrence in the thermal ablation groupwas 0.25 comparedwith the control group (95% confidence interval 0.13-0.48). Rates of adverse events were similar between the groups. CONCLUSIONS: In a multicenter randomized trial, thermal ablation of the post-EMR mucosal defect margin significantly reduced polyp recurrence at first surveillance colonoscopy, compared with no additional treatment. Routine implementation of this simple and safe technique could increase the utility of EMR, decrease surveillance burdens, and reduce morbidity and mortality from CRC. ClinicalTrials.gov no: NCT01789749.