Anastomotic leakage increases the risk of major low anterior resection syndrome 3 years after rectal cancer surgery.

[BACKGROUND] Anastomotic leakage is a serious complication following anterior resection for rectal cancer and may increase the risk of long-term bowel dysfunction. This study aimed to assess the long-term impact of anastomotic leakage on major low anterior resection syndrome (major LARS) at a uniform follow-up time.

[METHODS] We conducted a nationwide cohort study using the Swedish Colorectal Cancer Registry. Patients who underwent anterior resection for rectal cancer between 2015 and 2017 received the validated LARS questionnaire by mail 3 years after surgery. The primary outcome was major LARS among patients without a permanent stoma. Propensity score weighting was used to adjust for confounding, with covariates chosen using a directed acyclic graph. Sensitivity analyses included a dose-response analysis based on reoperation and an evaluation of a composite outcome of major LARS or permanent stoma.

[RESULTS] Of 1778 patients contacted, 1178 responded (66.2%). Among 1033 stoma-free patients, 52 (5.0%) had experienced a symptomatic anastomotic leak. Major LARS was reported in 69.2% and 52.9% of patients with and without leakage, respectively. Symptomatic anastomotic leakage increased the risk of major LARS (OR 2.09; 95% CI: 1.13-3.87) and this risk was higher in patients requiring reintervention (OR 2.78; 95% CI: 0.87-8.91) and when including permanent stoma in the outcome (OR 3.90; 95% CI: 2.20-6.91).

[CONCLUSION] Anastomotic leakage significantly increased the risk of major LARS 3 years after anterior resection for rectal cancer. These findings underscore the importance of preventing anastomotic leakage to reduce long-term functional morbidity in patients who survive rectal cancer.