Incidence, Risk Factors, and Prediction Model of Parastomal Hernia After Abdominoperineal Resection for Rectal Cancer.

Background: Parastomal hernia (PSH) is a frequent complication of abdominoperineal resection (APR), yet large-scale studies characterizing its long-term incidence and tools for individualized risk stratification remain lacking. To determine the long-term incidence, independent risk factors, and develop a clinical prediction model for PSH after APR in rectal cancer patients.

Methods: We conducted a retrospective cohort study of 836 patients with rectal adenocarcinoma who underwent APR and permanent end colostomy at a high-volume tertiary center (2014-2018). PSH was diagnosed according to the European Hernia Society criteria. Independent risk factors were identified using Cox regression, and a nomogram was developed to predict 1- to 5-year PSH probabilities. Model discrimination was assessed using time-dependent AUC.

Results: During a median follow-up period of 85 months, 207 patients (24.8%) developed PSH, with a cumulative incidence of 26.2% at 5 years. Independent risk factors included female sex (HR = 2.28, 95% CI: 1.73-3.01), age ≥ 60 years (HR = 5.17, 95% CI: 3.72-7.18), BMI ≥ 24 kg/m² (HR = 2.10, 95% CI: 1.57-2.80), and transperitoneal stoma route (HR = 4.11, 95% CI: 2.63-6.41; all P < 0.001). The nomogram demonstrated strong discrimination with 1-, 2-, 3-, 4-, and 5-year AUCs of 0.65, 0.70, 0.76, 0.80, and 0.83, respectively.

Conclusion: This study provides evidence on PSH incidence and risk factors, introducing a nomogram for personalized risk stratification. The nomogram allows clinicians to identify high-risk patients and tailor preventive strategies, such as extraperitoneal stoma creation or prophylactic mesh placement, to reduce PSH burden.