To investigate the effect and safety of endoscopic submucosal dissection (ESD) for treating rectal laterally spreading tumor (LST) extending to the dentate line.

Data of 45 cases of rectal LSTs extending to the dentate line were collected, which were treated by ESD in endoscopy center in Hubei Tumor Hospital from Oct 2012 to Oct 2014. The lesion types of LST, size, procedure time, the en-bloc complete resection rate, complications, pathological diagnosis and fellow-up were retrospective analyzed.

Among 45 LSTs in the rectum, average size of the lesion was 28 mm. en bloc R0 curative resection rate was 100%. The procedure time of ESD was 45 min~240 min, The average procedure time was (100±25) min. Delayed bleeding occurred in six patients (13.3%), all of which underwent successful endoscopic hemostasi. Perforation developed in 2 cases (4.4%), the perforation was cured by hemostat and conservative medical management. Thirty-seven cases were diagnosed post-surgically as low grade intraepithelial neoplasia and eight cases as high grade intraepithelial neoplasia, all of the lesion invasion was confined to mucosal layer. The average time of the follow-up was 30.2 months (10~46 months).None of the cases had recurrent or residual, and the anal defecation function was normal.

ESD was an effective and safe treatment for rectal LSTs for its high resection rate and low recurrence rate. ESD had no influence on the anal defecation function.