[Application of transanal total mesorectal excision in radical surgery for rectal cancer]

Transanal total mesorectal excision (taTME) is a novel operative approach of the radical surgery for rectal cancer, and has been a hot topic in colorectal surgery for years. TaTME aims to solve some problems from previous TME, such as exposure of peripheral mid-lower rectal space, judge of distal cutting margin, and to carry out completely minimal invasive operation. According to the degree of completion of different surgical approach, taTME can be divided into laparoscopic assisted taTME (hybrid taTME) and fully through the anal approach to complete the taTME (pure taTME). At present, the anal operation equipment suitable for taTME is divided into two types: transnasal endoscopic microsurgical platform (TEM-TME) and transnasal minimally invasive surgical platform (TAMIS-TME). Until now, there is no consensus on the indications of taTME. For the treatment of some special circumstances resulting in surgical difficulties, such as low rectal cancer, male, obesity, patients with narrow pelvis, tumor depth of invasion to the surrounding tissue, tumor diameter >4 cm, tissue distortions by neoadjuvant therapy and refractory benign disease, taTME has potential advantages. As for contraindications, obstructive rectal cancer, emergency surgery and advanced tumors should currently be regarded as contraindications of taTME. It was reported that taTME was safe and feasible, and had a satisfactory short-term outcomes in several centers in China. The operation is characterized by good TME quality, distal margin and circumferential margins, especially in overweight patients with narrow pelvis. The surgical principle is the eternal cornerstone to ensure the radical tumor resection and the safety of patients. The laparoscopic technique is widely used in China and surgeons are going to be skilled with laparoscopic surgeries for low rectal cancers. This situation postpones the development of taTME. It is challenging and disputing to advocate taTME to replace transabdominal laparoscopic surgery for low rectal cancer at recent times. If we have suitable instrument to dissect the root nodes and have the evidence from several ongoing clinical trials, we hope taTME could become a pure transanal approach because of its unique cosmetic superiority, without any abdominal invasive incisions.