Colon to Rectum
Gut. 2025;74(5):752-760
Margin thermal ablation eliminates size as a risk factor for recurrence after piecemeal endoscopic mucosal resection of large non-pedunculated colorectal polyps
Background: Lesion size is an independent risk factor for recurrence following endoscopic mucosal resection of large (≥ 20 mm) non-pedunculated colorectal polyps. Post-resection margin thermal ablation (MTA) reduces the risk of recurrence. Its impact on the uncommon larger (≥ 40 mm) lesions is unknown.
Objective: The authors sought to analyse the impact of MTA on ≥ 40 mm lesions in a large, prospective cohort.
Design: A prospective cohort of patients with colorectal polyps ≥ 20 mm treated with piecemeal endoscopic mucosal resection in an expert tissue resection centre was divided into 3 phases: ’pre-MTA’, July 2009–June 2012; ’MTA-adoption’, July 2012–June 2017 and ’standardised-MTA’, July 2017–July 2023. Recurrence was defined as adenomatous tissue endoscopically and/or histologically detected at the first surveillance colonoscopy. The primary outcome was the recurrence rate over the 3 time periods in 3 size groups: 20–39 mm, 40–59 mm and ≥ 60 mm.
Results: Over 14 years until July 2023, 1872 sporadic colorectal polyps ≥ 20 mm in 1872 patients underwent endoscopic mucosal resection (median lesion size 35 mm [interquartile range {IQR}, 25–45 mm]). Of these, 1349 patients underwent surveillance colonoscopy at a median of 6 months (IQR, 4–8 months). The overall rates of recurrence in the pre-MTA, MTA-adoption and standardised-MTA phases were 13.5% (42/310), 12.6% (72/560) and 2.1% (10/479), respectively, (p ≤ 0.001). When MTA was applied in the standardised-MTA phase, the rate of recurrence was the same among 20–39 mm (1.5% [3/205]), 40–59 mm (1.6% [3/190]) and ≥ 60 mm polyps (1.4% [1/73]) (p = 1.00).
Conclusion: Margin thermal ablation negates the effect of size on the incidence of recurrence after piecemeal endoscopic mucosal resection of colorectal polyps ≥ 40 mm.