MP72-06 MULTI-INSTITUTIONAL SURVIVAL ANALYSIS OF INCIDENTAL PATHOLOGIC T3A UPSTAGING IN CLINICAL T1 RENAL CELL CARCINOMA FOLLOWING PARTIAL NEPHRECTOMY

OBJECTIVE To evaluate whether incidental pathologic T3a (pT3a) upstaging after partial nephrectomy (PN) for clinical T1 disease results in inferior oncologic outcomes compared to pT1a-b disease. MATERIALS AND METHODS Retrospective chart review was completed at the University of Michigan and Moffitt Cancer Center to identify patients undergoing PN for clinical T1 masses between 1995 and 2015. A total of 1955 patients were identified, of which 95 had pT3a upstaging. Median follow-up was 38.2 months. Patients with pT3a disease were individually matched by clinicopathologic features with patients undergoing PN with pT1a-b disease in a 1:2 ratio. Kaplan-Meier analysis and univariate and multivariable Cox proportional hazards regression analysis were performed. Primary endpoint was recurrence-free survival (RFS). Secondary endpoints were all-cause mortality, cancer-specific survival (CSS), and rates of local and distant recurrence. RESULTS Recurrence rates were significantly higher in pT3a disease compared to pT1a-b controls (P