Impact of margin thermal ablation after cold-forceps avulsion with snare-tip soft coagulation for non-lifting large non-pedunculated colorectal polyps.

Objective: Non-lifting large non-pedunculated colorectal polyps (NL-LNPCPs) account for 15% of LNPCP and are effectively managed by Endoscopic Mucosal Resection with adjunctive Cold-forceps Avulsion with adjuvant Snare-Tip soft coagulation (CAST). However, recurrence rates > 10% at surveillance colonoscopy is a significant limitation. We aimed to compare the outcomes of CAST with MTA versus CAST alone for NL-LNPCPs.

Methods: Prospective observational data on consecutive patients with NL-LNPCPs treated by EMR and CAST at a single tertiary center was retrospectively evaluated. Two cohorts were established: the pre-MTA period (January 2012-June 2017) and the MTA period (July 2017-October 2023). The primary outcome was the residual/recurrent adenoma (RRA) rate at first surveillance colonoscopy (SC1). Secondary outcomes included RRA at SC2 and adverse events.

Results: Over 142 months, 300 patients underwent EMR and CAST for LNPCP: 103 lesions pre-MTA and 197 with MTA. At SC1 and SC2, recurrence was lower in the MTA cohort compared to the pre-MTA cohort (5.0% vs. 18.8%, p<0.001 and 0.8% vs. 10.0%, p<0.001, respectively). Adverse events were similar between the two cohorts [deep mural injury types III-V (pre-MTA 2.9% vs MTA 5.6%, p=0.29), delayed bleeding (pre-MTA 8.7% vs MTA 7.1%, p=0.49)]. On multivariate analysis, MTA was the only variable independently associated with a reduced likelihood of recurrence (OR 0.20, 95% CI 0.07-0.54; P = 0.001).

Conclusions: For NL-LNPCPs, MTA in combination with CAST is safe and effective and reduces recurrence at SC1 in comparison to CAST alone.