Comparable long-term efficacy of cold and hot EMR of large colon polyps – follow up results of a randomized trial

Aims Although safer, cold endoscopic mucosal resection (EMR) of large (≥ 20 mm) non-pedunculated polyps has been shown to have a high recurrence rate of>25% at first surveillance colonoscopy (SC1). The efficacy of treating recurrence at SC1 is unknown. The aim of this study was to compare recurrence between cold and hot EMR of large non-pedunculated colorectal polyps at second surveillance colonoscopy (SC2).

Methods This is a follow-up study of a randomized trial of 660 patients undergoing cold or hot EMR of large non-pedunculated colorectal polyps at 15 centers in the US and Canada. We performed an interim analysis of all patients who have completed SC2. Treatment of recurrence was at the discretion of the endoscopist. Primary outcome of interest was recurrence/residual rate of neoplastic polyps at SC2. Secondary outcomes include proportion of polyps with no recurrence at S1, but recurrence at SC2. We further examined characteristics of recurrent/residual polyps.

Results 273 patients (44% of surveillance eligible patients) with 281 large polyps completed SC2 with examination of the resection site after a median of 19 months (148 in the cold EMR group and 125 in the hot EMR group). Among these patients, recurrence at SC1 was significantly greater following cold EMR (36.3%) compared to hot EMR (16.9%). Recurrence at SC2 was not different and occurred 12.7% in the cold EMR group and in 8.9% in the hot EMR group (p=0.304). Among those with recurrence at SC1, complete removal with no recurrence at SC2 was more often achieved in in the cold EMR group (80.7%) compared to the hot EMR group (57.1%, p=0.035). The proportion of polyps with no recurrence at SC1 but detected recurrence at SC2 was 5.7% and 1.6% (p=0.127), respectively. Recurrent median polyp size was similar (10 and 8 mm, respectively). Histology of recurrent polyps was also similar with 90.0% adenomas (5 tubulo-villous adenomas [TVA]) and 10.0% sessile serrated lesions (SSL) in the cold EMR group and 72.7% adenomas (2 TVA), 27.2% SSL (1 dysplastic) in the hot EMR group. One polyp in the hot EMR group contained high grade dysplasia; there was no cancer in any recurrent polyp. All recurrent polyps at SC2 could be removed.

Conclusions In this large follow-up study long-term efficacy of cold EMR of large non-pedunculated polyps appears comparable to hot EMR at second surveillance colonoscopy, although incomplete SC2 follow-up data is a limitation. Management of recurrence is equivalent between cold and hot EMR. The high rate of new recurrence at SC2 after cold EMR suggests that SC1 biopsies should be taken even in the absence of visible recurrence (in contrast to hot EMR). Overall, the results lower concerns of an initial high recurrence rate following cold EMR, and that early recurrence can be adequately managed. ClinicalTrials.gov no: NCT03865537.

Publication History

Article published online:
27 March 2025