Abstract: Objective To evaluate the efficacy and safety of endoscopic submucosal dissection (ESD) in the treatment of low rectal early cancer. Methods The data of 449 patients (269 male,59.9%)with early colorectal cancer who underwent ESD treatment and were pathologically diagnosed from January 2016 to Decmeber 2020 in the Department of Gastroenterology of Beijing Friendship Hospital were retrospectively analyzed. The average age of the patients was (63.90±9.99) years, and the median size of the lesion was [20(14,27)]mm. The patients were divided into low rectum group (n=48) and control group(n=401), according to the different locations of lesions. The clinicopathological characteristics, operation time, en bloc resection rate, R0 resection rate, and complications were compared with each other between the two groups. Results There were no significant differences in gender ratio and age between the two groups. The median size of lesions was [20.5(15,34.5)]mm in the low rectum group and [19(13,27)]mm in the control group, with a significant difference. The median operation time was [60(33.25,88.75)]min in the low rectum group and [40(25,60.5)]min in the control group. The rate of invasion depth of submucosal in the low rectum group was 22.9%, which was significantly higher than that in the control group (10.7%). There were no significant differences in the en bloc resection rate, complete resection rate, and postoperative complication rate between the two groups. Conclusion ESDtreatment of low rectal early cancer took longer operation time than that of the other colorectal parts. The possibility of deep submucosal invasion was higher. On the premise of fully evaluating the indications, ESD was a safe and effective treatment for low rectal early cancer.

Key words: endoscopic submucosal dissection (ESD), noninvasive early gastrointestinal cancer, low rectum