Primary Resection with Bladder Preservation for Colovesical Fistula: Clinical Outcomes and the Prognostic Significance of Perineural Invasion

BackgroundThis study evaluated the safety and efficacy of primary resection and anastomosis (PRA) for colovesical fistula (CVF) of diverse etiologies and identified independent prognostic factors for oncological outcomes. MethodsWe retrospectively analyzed 112 CVF patients (2017-2024) undergoing PRA with or without a defunctioning stoma, comparing clinical outcomes across benign and malignant cohorts. ResultsBenign etiologies accounted for 33.0% (n=37) (colonic diverticulitis (n=19, 51.4%), Crohns disease (n=14, 37.8%), and iatrogenic injury (n=4, 10.8%)), all underwent PRA with partial cystectomy, achieving zero mortality and no recurrence. Malignancies (67.0%) primarily included colorectal adenocarcinoma (sigmoid colon cancer (n=44, 58.7%) or rectal cancer (n=31, 41.3%)). Within the malignant cohort, radical cystectomy (n=15) was strictly necessitated by advanced disease features, including distal tumor location and extensive bladder wall invasion (80.0% vs 36.7%, P=0.003). Consequently, this advanced cohort experienced longer operative times (589 vs. 289 min), higher blood loss (600 vs. 100 mL), increased morbidity (80.0% vs. 20.0%, P<0.001), and shorter disease-free survival (DFS) (8 vs. 20 months, P=0.008) compared to those amenable to partial cystectomy (n=60). Crucially, multivariate analysis identified perineural invasion (PNI) (HR: 3.83, 95% CI: 1.49-9.84; P=0.005) as a critical independent predictor of recurrence, reflecting the impact of tumor biology over surgical extent. ConclusionsPRA is a definitive and versatile strategy for CVF. In malignant cases, bladder-preserving strategies are oncologically viable when R0 margins are achievable. Integration of PNI status and neoadjuvant therapy was essential for refining personalized multidisciplinary management.