Transanal endoscopic microsurgery is the main treatment option for rectal tumors such as large adenoma, early cancer because of lower complications and mortality rates and shorter hospital stays rather than conventional surgery. Particularly, However, transanal endoscopic microsurgerymust be performed under either general or spinal anesthesia, and expensive surgical instruments are required. Colorectal endoscopic submucosal dissection is a novel endoscopic procedure that enables en bloc resection of benign colorectal lesions and early colorectal cancer. Endoscopic submucosal dissectioncan be performed under conscious sedation without anesthesia, and there are fewer hospital days than those for transanal endoscopic microsurgery. In the present study, we compared the treatment efficacy and safety between endoscopic submucosal dissectionand transanal endoscopic microsurgery for the treatment of early rectal neoplasms and large rectal adenomas.

Inclusion Criteria:

• The lower and upper borders of the adenoma or early rectal cancer are located at ≥2 cm and ≤15 cm from the anal verge, respectively.
• Have signed approved informed consent form for the study
• preoperative stage uT0 and/or uT1, mrT0 and/or mrT1

Exclusion Criteria:

• non-epithelial tumors
• tumors \