Clinicopathological evaluation of the efficacy of endoscopic treatment for sessile serrated lesions comparing endoscopic mucosal resection, cold snare polypectomy, and underwater endoscopic mucosal resection

Objectives: Recently, various endoscopic treatments for colorectal polyps have been reported, including cold snare polypectomy (CSP) and underwater endoscopic mucosal resection (UEMR), in addition to EMR. However, a precise treatment strategy for sessile serrated lesions (SSL) has not been established. In this study, we analyzed the clinicopathological features of SSL resected by EMR, CSP, and UEMR to determine the most suitable treatment for SSL.

Methods: A total of 92 SSL resected via EMR (n = 11), CSP (n = 36), and UEMR (n = 45) were retrospectively enrolled between February 2021 and October 2022. To evaluate pathological findings, we examined SSL samples, which were stretched before formalin fixation and sectioned at 2-mm intervals. Primary outcomes were the R0 resection rate and thickness of submucosal (SM) tissue specimens for each treatment. In addition, we evaluated SSL with dysplasia (SSLD) and the inverted growth pattern which may affect the vertical margin.

Results: The R0 resection rate significantly differed among the three groups (EMR, 73%; CSP, 42%; UEMR, 87%, p = 0.001). The median thickness of SM tissue resected by CSP (0 µm) was significantly less than that by EMR (362 µm) and UEMR (325 µm; p < 0.001). All four SSLDs were diagnosed endoscopically. Five SSLs with inverted growth patterns were pathologically diagnosed. Of these, two SSLs with inverted growth patterns could not be diagnosed endoscopically.

Conclusions: UEMR is considered to be a suitable treatment option for SSL. CSP results were pathologically insufficient. Therefore, surveillance to evaluate local recurrence is important, and the results of further multicenter prospective studies should be referred.