Histopathological vertical margin positivity in cold snare polypectomy and mucosal resection for sessile serrated lesions

Background and Aims Evidence regarding the status of the vertical margin of sessile serrated lesions (SSLs) resected using cold snare polypectomy (CSP) is lacking, and whether a histopathologically positive vertical margin is related to recurrence remains unclear. Therefore, this preliminary study aimed to clarify the rates of positive or unevaluable vertical and horizontal margins and the rate of muscularis mucosae resection in SSLs treated using CSP compared with those treated with endoscopic mucosal resection (EMR). Methods Histological outcomes of patients treated with CSP or EMR for SSL were evaluated in this single-center observational study. The primary outcome was the incidence of histopathologically positive vertical margins in CSP and EMR. Furthermore, the comparisons were adjusted for confounding factors using propensity score matching. Results Overall, 82 patients with SSLs were included in the CSP and EMR groups after matching. The incidence of positive histological vertical margins in the CSP and EMR groups were 67.1% and 2.4%, respectively (p<0.001). Regarding the evaluation of the presence of muscularis mucosae, 29.3% and 98.8% of the patients in the CSP and EMR groups, respectively, had a complete muscularis mucosae resection (p<0.001). Conclusions A rigorous histopathologic evaluation revealed that for SSLs, CSP more frequently leads to positive vertical margins than EMR.