Postoperative sepsis is a serious complication of rectal cancer surgery and contributes to increased morbidity and mortality. This study aimed to identify risk factors and etiologies associated with postoperative sepsis in patients undergoing rectal surgery. A retrospective cohort study was conducted at a single center, including patients with rectal cancer who underwent surgery between November 2018 and February 2023. Tumors located <5 cm from the anal verge were treated with abdominoperineal resection (APR). Recorded variables included age, sex, surgical approach, tumor location, comorbidities (cardiovascular disease, diabetes, obesity), and loco-regional septic complications (fistula, abscess). A P value < 0.05 was considered statistically significant. A total of 226 patients underwent APR or low anterior resection (LAR). APR was associated with higher odds of early (OR = 1.84, 95% CI, 0.52–6.53; P = 0.14), late (OR = 2.75, 95% CI, 0.81–9.39; P = 0.13), and overall septic complications (OR = 2.38, 95% CI, 0.96–5.91; P = 0.06) compared with LAR; however, these differences were not statistically significant. After LAR, anastomotic leakage was the leading cause of postoperative sepsis (4.67%), including five early (<7 days) and three late (>7 days) fistulas. In the APR group, two patients developed late pelvic abscesses. Parastomal hernia was the most common late complication after APR. Postoperative loco-regional sepsis was more frequent in patients older than 50 years and in those with comorbidities, although no statistically significant association was observed overall. The median hospital stay was 11.7 days.
