Objective To investigate the risk factors for abdominal infection after low anterior resection (LAR) for rectal cancer.

Methods The retrospective cohort study was conducted. The clinico-pathological data of 182 patients with rectal cancer who underwent LAR at Peking University Cancer Hospital from January 2017 to December 2020 were collected. There were 119 males and 63 females, aged 61(53,67) years. All patients underwent LAR for rectal cancer, and prophylactic stoma was performed according to specific conditions of patients and surgeon experiences. Observation indica-tors: (1) occurrence of abdominal infection after LAR for rectal cancer; (2) analysis of risk factors for abdominal infection after LAR for rectal cancer; (3) impact of prophylactic stoma on complications after LAR for rectal cancer. Comparison of measurement data with skewed distribution between groups was conducted using the Mann‑Whitney U test. Comparison of count data between groups was conducted using the chi‑square test or Fisher exact probability. Univariate analysis was conducted using the corresponding statistical methods according to the type of data. Variables with P<0.10 in univariate analysis and clinical confounding factors were included in multivariate analysis, and the Logistic regression model was used for multivariate analysis.

Results (1) Occurrence of abdominal infection after LAR for rectal cancer: among the 182 patients, 22 cases developed postoperative abdominal infection, including 14 cases of anastomotic leakage and 8 cases of other abdominal infections. Among the 14 patients with anastomotic leakage, 10 cases were classified as Clavien-Dindo grade Ⅱ, 2 cases as Clavien‑Dindo grade ⅢA, and 2 cases as Clavien‑Dindo grade ⅢB. Among the 8 patients with other abdominal infections, 2 cases were classified as Clavien‑Dindo grade Ⅰ and 6 cases as Clavien‑Dindo grade Ⅱ. (2) Analysis of risk factors for abdominal infection after LAR for rectal cancer: results of multivariate analysis showed that history of abdominal surgery and post-operative paralytic ileus were independent risk factors for abdominal infection after LAR for rectal cancer (odds ratio=2.99, 13.90, 95% confidence interval as 1.02-8.73, 3.63-53.16, P<0.05). (3) Impact of prophylactic stoma on complications after LAR for rectal cancer: among the 182 patients, 77 cases underwent prophylactic stoma and 105 did not undergo prophylactic stoma. The number of post-operative abdominal infection in patients with and without prophylactic stoma was 6 and 16, respec-tively, showing no significant difference between them (χ²=2.32, P>0.05). The number of postopera-tive anastomotic leakage in patients with and without prophylactic stoma was 1 and 13, the number of postoperative paralytic ileus in patients with and without prophylactic stoma was 12 and 5, respectively, showing significant differences in above indicators between them (χ²=7.68, 6.14, P<0.05).

Conclusions History of abdominal surgery and postoperative paralytic ileus are independent risk factors for abdominal infection after LAR for rectal cancer. Prophylactic stoma is associated with reduction in postoperative anastomotic leakage, however, there is no significant difference in ratio of abdominal infection after LAR for rectal cancer between patients with and without prophylactic stoma.