Previously Attempted Large Nonpedunculated Colorectal Polyps Are Effectively Managed By Endoscopic Mucosal Resection

INTRODUCTION: Endoscopic mucosal resection (EMR) is an effective therapy for naive large nonpedunculated colorectal polyps (N-LNPCPs). The best approach for the treatment of previously attempted LNPCPs (PA-LNPCPs) is undetermined.METHODS: EMR performance for PA-LNPCPs was evaluated in a prospective observational cohort of LNPCPs >= 20 mm. Efficacy was measured by technical success (removal of all visible polypoid tissue during index EMR) and recurrence at first surveillance colonoscopy (SC1). Safety was assessed by clinically significant intraprocedural bleeding, deep mural injury types III-V, clinically significant post-EMR bleeding, and delayed perforation.RESULTS: From January 2012 to October 2019, 158 PA-LNPCPs and 1,134 N-LNPCPs underwent EMR. Median PA-LNPCP size was 30 mm (interquartile range 25-46 mm). Technical success was 93.0% and increased to 95.6% after adjusting for 2-stage EMR. Cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST) was required for nonlifting polypoid tissue in 73 (46.2%). Median time to SC1 was 6 months (interquartile range 5-7 months). Recurrence occurred in 9 (7.8%). No recurrence was identified among 65 PA-LNPCPs which underwent margin thermal ablation at SC1 vs 9 (18.0%; P < 0.001) which did not. There were significant differences in resection duration (35 vs 25 minutes; P < 0.001), technical success (93.0% vs 96.6%; P = 0.026), and use of CAST (46.2% vs 7.6%; P < 0.001), between PA-LNPCPs and N-LNPCPs. When adjusting for 2-stage EMR, no difference in technical success was identified (95.6% vs 97.8%; P = 0.100). No differences in adverse events or recurrence were identified.DISCUSSION: EMR, using auxillary techniques where necessary, can achieve high technical success and low recurrence frequencies for PA-LNPCPs.[GRAPHICS]