Incidence and risk factors for peritoneal carcinomatosis following open radical cystectomy.

<bold>Objective: </bold>To characterize the frequency and risk factors of peritoneal carcinomatosis (PC) in patients undergoing open radical cystectomy (RC).<bold>Methods: </bold>We identified 3,285 patients with urothelial carcinoma treated with RC for curative intent between 1980 and 2016. At last follow-up, 72.1% (2,370/3,285) of patients had died, with a median follow-up of 8.6 years (Interquartile Range, (IQR) 3.7, 14.1). PC was defined as any recurrence involving the omentum, small bowel, and mesentery. Overall-specific survival (OSS) and cancer-specific survival (CSS) was evaluated using Kaplan-Meier methodology and log-rank test. Risk factors for mortality and recurrence were performed using Cox proportional hazards regression models.<bold>Results: </bold>One hundred and twenty nine (3.9%) patients were diagnosed with PC, while a total of 1,148 (34.9%) patients experienced recurrence at other sites. Median time to PC vs. other-site recurrence was 1.3 (IQR 1.3, 2.3) and 0.9 (IQR 0.5, 2.1) years, respectively (P= 0.04). Only increasing pathologic stage on multivariable analysis was associated with developing PC (pT1 HR 2.51, 95CI 1.14-5.55, P= 0.02; pT2 OR 2.82, 95CI 1.47-5.43, P= 0.002; pT3+ 2.40, 95CI 1.31-4.42, P= 0.005) over other recurrence patterns. Nodal status and tumor margin status were not associated. Patients with PC experienced worse OSS and CSS than other types of recurrence (P< 0.001).<bold>Conclusion: </bold>PC was identified in almost 4% of patients undergoing open RC. PC is a rare occurrence after RC and primarily impacts patients with locally advanced disease. [ABSTRACT FROM AUTHOR]