Extraperitoneal colostomy reduces parastomal hernia after laparoscopic abdominoperineal resection: a propensity score–matched study

PURPOSE: Parastomal hernia (PSH) is one of the most frequent long-term complications following abdominoperineal resection (APR) for rectal cancer. The optimal colostomy route to minimize PSH remains controversial. This study aimed to compare PSH risk between extraperitoneal colostomy (EPC) and transperitoneal colostomy (TPC) after laparoscopic APR. METHODS: A retrospective cohort study was conducted including patients who underwent laparoscopic APR for rectal cancer between 2014 and 2017. Patients were categorized according to colostomy route (EPC vs. TPC). The primary endpoint was PSH, and secondary endpoints included other short- and long-term stoma-related complications and perioperative outcomes. Propensity score matching (1:3) was applied to balance baseline characteristics. Risk factors for PSH were further analyzed using logistic regression. RESULTS: A total of 464 patients were included. After matching, 102 patients in the EPC group and 243 in the TPC group were analyzed. Perioperative outcomes and overall stoma-related complication rates were comparable between groups. However, PSH occurred less frequently in the EPC group than in the TPC group (10/102 [9.8%] vs. 79/243 [32.5%], P < 0.001). Multivariate logistic regression demonstrated that EPC was an independent protective factor against PSH (OR 0.190, 95% CI 0.089-0.406, P < 0.001), whereas increasing age and female sex were significant risk factors. CONCLUSION: Extraperitoneal colostomy was associated with a lower risk of PSH after laparoscopic APR for rectal cancer without increasing perioperative morbidity. These findings support consideration of the extraperitoneal route in experienced centers to improve long-term stoma outcomes, while prospective multicenter studies are needed for further validation.