MP42-20 SURVIVAL OUTCOMES OF PT3A PATHOLOGICAL UPSTAGING IN PARTIAL VS. RADICAL NEPHRECTOMY FOR RENAL CELL CARCINOMA

Abstract

INTRODUCTION AND OBJECTIVE: Partial nephrectomy (PN) is the preferred surgical treatment of Kidney confined tumors, as it can preserve renal function without compromising oncologic control when compared to radical nephrectomy (RN) . However, a proportion of patients will be diagnosed with more aggressive pT3a disease at time of surgery, potentially negating the benefits of PN and compromising the oncologic and survival outcomes. Therefore, we aimed to identify predictors of pT3a upstaging, and compare recurrence-free (RFS) and overall survival (OS) between patients who upstaged after PN versus RN. METHODS: A multi-institutional database of 4,406 RCC patients was queried to identify patients who underwent PN or RN for cT1-cT2 tumors between 2007 and 2020. Patients were further stratified according to pT3a upstaging, and descriptive statistics were utilized to summarize baseline characteristics between the study groups. Multivariate logistic regression model was fitted to identify predictors of upstaging, and the Kaplan-Meier method was utilized to characterize OS and RFS in the study population. Cox proportional hazards model was used to identify predictors of survival. RESULTS: A total of 4,406 patients were investigated, of which 397 (8.9%) were post-operatively upstaged to pT3a. Of those, 146 (39%) underwent PN and 227 (61%) underwent RN. Multivariate analysis identified Fuhrmann grades 3 and 4 (OR 4, CI 1.5 - 10, p=0.005; and 13.6, CI 2.8 - 64.8; respectively, p=0.001), cT2 stage (OR 4.2, CI 1.8 - 9.6, p=0.001) as independent predictors of upstaging. In addition, black patients were less likely to upstage compared to white (OR 0.16, CI 0.05 - 0.53, p=0.003). 5-year RFS for upstaged patients after PN was 78% (CI 54% - 90%) and 30% (CI 15% - 48%) after RN (p=0.021). 5y-RFS in upstaged cT1 patients who underwent PN vs. RN was 84% (CI 58% - 95%) and 49% (CI 18% - 74%), respectively. In upstaged cT2 patients, 5y-RFS after RN was 21% (CI 5%-43%). Five-year OS for upstaged patients overall was 97% (CI 82% - 99%) after PN and 50% (CI 31% - 67%) after RN. 5y-OS in upstaged cT1 patients was 100% after PN vs. 45% (CI 19%-69%) after RN. Cox proportional hazards model identified cT2 stage as an independent predictor of RFS (HR 3.43, CI 1.05 - 11.2, p=0.041). CONCLUSIONS: No OS differences were noted in pT3a upstaged patients who underwent PN vs. RN. Moreover, PN conferred a RFS advantage in this population.