Radical surgery for rectal cancer has evolved from the initial concept of total mesorctal excision (TME) to the wide application of laparoscopic surgery in the radical treatment of rectal cancer. After 30 years' rapid development, nowdays laparoscopic TME surgery for rectal cancer has become the first choice for those patients with rectal cancer. However, the auxiliary incision of the abdominal wall which is used to remove tumor specimens is contrary to the current concept of minimally invasive surgery. Avoiding abdominal wall incisions has become a common appeal of gastrointestinal surgeons and patients with rectal cancer. Natural orififice specimen extraction surgery (NOSES) can solve the problem of abdominal wall auxiliary incision, which complete rectal cancer radical resection and gastrointestinal reconstruction under the full laparoscopic. The specimens are taken out through the natural orifice (rectum or vagina) without an auxiliary incision, which is more in line with minimally invasive practice and easier to operate. Researching on the progress of laparoscopic radical resection of rectal cancer in NOSES aims to provide a certain reference for this operation.

Inclusion Criteria:

• The inclusion criteria were as follows: (1) patients aged between 18 and 80 years; (2) histopathology confirmed as colorectal adenocarcinoma; (3) preoperative imaging (CT and MR) assessments showed that colorectal cancer did not penetrate the serosa (≤T3); (4) tumor circumference <5 cm; (5) enhanced chest and abdominal pelvic CT scans before operation excluded liver metastasis, lung metastasis, and other distant organ metastases.

Exclusion Criteria:

• The preoperative exclusion criteria were as follows: (1) tumors could be resected by endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR); (2) body mass index (BMI) > 30 kg/m2; (3) patients with severe perforation, bleeding, or obstruction requiring emergency surgery; (4) recurrent cases; (5) patients undergoing neoadjuvant therapy or preoperative radiotherapy; (6) Anesthesiologists (ASA) score ≥ IV; (7) active period of infection; (8) blood neutrophils <3 × 109/L.