Abstract: Objective To investigate the feasibility of endoscopic submucosal dissection(ESD) in rectal lesions extending to the dentate line. Methods The clinical data of 30 patients who underwent ESD in Beijing Friendship Hospital from October 2015 to February 2021 because of the rectal lesions extending to the dentate line were collected retrospectively in this study. Clinical characteristics including age, gender, lesion morphology, and lesion size were collected to illustrate the base lines of patients. The safety and effectiveness of ESD were accessed by analyzing procedure time, En bloc resection rate, complete resection rate, adverse events and recurrences rate of these patients. Results The mean procedure time of ESD was (89.83±49.55)min, En bloc resection rate was 93.0% (28/30), and complete resection rate was 90% (27/30). Histopathologic examinations of the resection samples showed that 23 cases of adenoma (7 cases of low-grade intraepithelial neoplasia and 16 cases of high-grade intraepithelial neoplasia), 6 cases of intramucosal adenocarcinoma, and 1 case of submucosal adenocarcinoma (SM2) were included in these patients. About the complication of ESD, perforation occurred in 3 cases and delayed bleeding occurred in 4 cases. All complications were successfully resolved under endoscopy management. The average follow-up time was (3.33±1.44) years. No recurrences, anal stenosis and defecation difficulties events were observed during the follow-up period in all patients. Conclusion As a minimal invasive way for curable treatment, ESD is safe and feasible for rectal lesions extending to the dentate line.

Key words: rectal lesions, dentate line, endoscopic submucosal dissection (ESD), safety, feasibility