1.Proposal of the principle of TME surgery In 1982, Heald first proposed the concept of total rectal mesenteric resection. 1982, he reported 50 cases of TME surgery for rectal cancer, and none of them had local recurrence after 2 years; in 1992, he reported 152 cases of TME surgery for rectal cancer, and the local recurrence rate was only 2.6%. In the 1990s, the concept of TME was introduced into China. 2. Contents of TME principles Broadly speaking, the pelvic visceral layer is sharply separated from the mural fascia under direct vision to the level of the anal raphe. In a narrow sense, the resection plane of the rectal mesentery should be 5 cm below the lower edge of the tumor, i.e. 2+3 gold standard: 2 cm of the distal intestinal canal of the tumor is resected, and then 3 cm of the distal rectal mesentery is resected. During the operation, the anterior sacral fascia and the visceral fascia are not damaged. Heald compared Miles surgery and TME for low rectal cancer within 5 cm from the anal verge, and TME increased the rate of anal preservation to 77%. According to the report of Zhongshan University in China, standardized TME can increase the anal preservation rate of low rectal cancer from 44.9% to 76.2%, and increase the possibility of preserving the anal sphincter by 31.3%. 4. TME reduces local recurrence rate The Swedish Collaborative Group reported that TME can reduce the local recurrence rate of conventional surgery by at least 50%. Data from the North American Treatment Cooperative Group showed that the 5-year local recurrence rate was 5% in the TME alone group and 13.5% in the conventional surgery plus postoperative radiotherapy and chemotherapy. Domestic scholars generally believe that standardized TME can make the postoperative local recurrence rate of low rectal cancer controlled to less than 10%.