Oncological Outcomes for Patients Harboring Positive Surgical Margins Following Radical Cystectomy for Muscle-Invasive Bladder Cancer: A Retrospective Multicentric Study on Behalf of the YAU Urothelial Group.

Introduction: Adjuvant therapy has no defined role for patients with positive surgical margins (PSMs) following radical cystectomy (RC) for muscle-invasive bladder cancer (MIBC). The aim of our study was to describe loco-regional recurrence-free survival (LRFS), metastatic-free survival (MFS), recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS) and identify predictors of each endpoint in patients with PSMs following RC for MIBC. Methods: A collaborative retrospective cohort study was conducted on 394 patients with PSMs who underwent RC for MIBC between January 2000 and December 2018 at 10 tertiary referral centers. Patients receiving perioperative radiotherapy were excluded from the study. Kaplan−Meier curves were used to estimate patient survival. Cox regression analysis was used to identify predictors of survival. Results: Median age at surgery was 70 years (IQR 62−76) with 129 (33%) and 204 (52%) patients had pT3 and pT4 tumors, respectively. Nodal metastasis (pN+) was identified in 148 (38%). Soft tissue PSMs were found in 283 (72%) patients, urethral PSMs in 65 (16.5%), and ureteral PSMs were found in 73 (18.5%). The median follow-up time was 44 months (95% CI 32−60). Median LRFS, MRFS, RFS, CSS, and OS were 14 (95% CI 11−17), 12 (95% CI 10−16), 10 (95% CI 8−12), 23 (95% CI 18−33), and 16 months (95% CI 12−19), respectively. On multivariable Cox regression analysis, the pT3−4 stage, pN+ stage, and multifocal PSMs were independent predictors of LRFS, MRFS, RFS, and OS. Adjuvant chemotherapy improved all oncological outcomes studied (p < 0.05). The number of lymph nodes removed was independently associated with better LRFS, MRFS, and RFS. Advanced age at diagnosis was independently associated with worse OS. Conclusion: Patients with PSMs following RC have poor outcomes since half of them will recur within a year and will die of their disease. Among all PSMs types, patients with multifocal PSMs harbor the worst prognosis. We observed a benefit of adjuvant chemotherapy, but clinical trials evaluating innovative adjuvant strategies for these patients remain an unmet need.