A133 MARGIN THERMAL ABLATION WITH SNARE-TIP SOFT COAGULATION EFFECTIVELY MITIGATES RECURRENCE AFTER ENDOSCOPIC MUCOSAL RESECTION OF LARGE NON-PEDUNCULATED COLORECTAL POLYPS

Abstract Background Recurrence following endoscopic mucosal resection (EMR) historically occurs in approximately 15-20% of large (≥20 mm) non-pedunculated colorectal polyps (LNPCPs). Margin thermal ablation with snare-tip soft coagulation (STSC) of the post-EMR defect is an evidence-based modality to mitigate recurrence. However, international validation of margin thermal ablation outcomes is needed. Aims To evaluate the frequencies of endoscopic and histologic recurrence following margin thermal ablation with STSC for LNPCPs managed by EMR. Methods Consecutive patients ampersand:003E 18 years of age who underwent endoscopic resection for a LNPCP were enrolled in a prospective single center observation cohort study (clinicaltrials.gov ID: NCT05402696). Of those lesions which underwent successful EMR, margin STSC was applied systematically aiming to create at least a 2-3mm rim of completed ablated tissue (complete whitening). Recurrence was evaluated both endoscopically, using a standardized protocol for the post-EMR scar, and histologically. Results From 06/2022-09/2023, 335 LNPCPs were endoscopically resected, including 209 by EMR. Following successful EMR, 182 (87.1%) underwent margin STSC. Of these lesions, 49 LNPCPs in 46 patients were assessed at first surveillance colonoscopy. Margin STSC was complete for 44 (89.8%) lesions and incomplete for 5 (10.2%) due to difficult angulation/positioning (n=3) and ileocecal valve location (n=2). Median interval to first surveillance colonoscopy was 6 (IQR 6-7) months. There was no evidence of recurrence noted on endoscopy. Biopsy was performed in 44 (89.8%) with no evidence of histologic recurrence. Conclusions Thermal ablation of the defect margin with STSC effectively negates recurrence and should be considered standard of care following EMR. Funding Agencies None