Objective To investigate the incidence and influencing factors of anastomotic leakage after laparoscopic anterior resection for rectal cancer.

Methods The retrospective case-control study was conducted. The clinicopathological data of 804 patients with rectal cancer who were admitted to Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from January 2017 to December 2019 were collected. There were 521 male and 283 female, aged 63(range, 27-94)years. All 804 patients underwent laparoscopic anterior resection for rectal cancer. Observation indicators: (1) surgical situations; (2) incidence of postoperative anastomotic leakage; (3) follow-up; (4) influencing factors of postoperative anastomotic leakage; (5) subgroup analysis. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribu-tion were represented as M(range), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Univariate analysis was conducted using the chi-square test or independent sample t test. Factors with P≤0.2 in univariate analysis were included in multivariate Logistic regression analysis.

Results (1) Surgical situations. All 804 patients underwent laparoscopic radical resection of upper and middle rectal cancer successfully, with the operation time and volume of intraoperative blood loss as 135(range, 118-256)minutes and 30(range, 5-350)mL. All 804 patients completed end-to-end colon rectal anastomosis, including 287 patients with reinforced sutures at the anastomotic site, and 517 patients with routine anastomosis. (2) Incidence of postoperative anastomotic leakage. Of the 804 patients, 40 patients had postoperative anastomotic leakage, with the incidence rate as 4.98%(40/804). (3) Follow-up. All 804 patients were followed up for 32(range, 6-49)months. None of patient died during the perioperative period. (4) Influencing factors of postoperative anastomotic leakage. Results of multivariate analysis showed that unreinforced suture at the anastomotic site was an independent risk factor for postoperative anastomotic leakage (odds ratio=2.78, 95% confidence interval as 1.21-6.37, P<0.05). (5) Subgroup analysis. Of the 804 patients, 202 patients received neoadjuvant therapy and 602 patients did not receive neoadjuvant therapy. Of the 602 patients who did not receive neo-adjuvant therapy, cases with postoperative anastomotic leakage was 6 in the 253 patients with reinforced sutures, versus 21 in the 349 patients with routine sutures, showing a significant difference between them (χ²=4.56, P<0.05).

Conclusion Unreinforced anastomosis at the anasto-motic site is an independent risk factor for anastomotic leakage after laparoscopic anterior rectal resection, especially for rectal cancer patients without neoadjuvant radiochemotherapy.