Abstract: Objective To investigate the risk factors of anastomotic leakage after total laparoscopic transanal natural orifice specimen extraction surgery (NOSES Ⅳ) for colorectal cancer. Methods The clinicopathological data of 268 patients with colorectal cancer who underwent NOSES Ⅳ in the Cancer Hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College and Luanzhou People's Hospital from January 2016 to June 2023 were retrospectively analyzed. Patients were divided into the anastomotic leakage group (n=27) and the non⁃anastomotic leakage group (n=241) according to the occurrence of anastomotic leakage. The risk factors were analyzed by both univariable and multivariable logistic regressions. Results The incidence of anastomotic leakage after NOSES Ⅳ for colorectal cancer was 10.1%. The univariable analysis showed that the male patients with tumor distance <8 cm from anal margin and operation time ≥140 min were associated with anastomotic leakage. The multivariable logistic regression analysis showed that a duration of operation ≥140 min was an independent influential factor of postoperative anastomotic leakage in patients who underwent NOSES Ⅳ for colorectal cancer (OR=5.987, 95%CI: 1.519-23.602, P=0.011) Conclusions Operation time is a influential factor for anastomotic leakage after NOSES Ⅳ for colorectal cancer.

Key words: Anastomotic leakage, Colorectal cancer, Natural orifice specimen extraction, Risk factor