Impact of cytoreductive nephrectomy (CN) on survival in metastatic renal cell cancer (mRCC) treated with immune checkpoint inhibitors (ICI).

Abstract

359 Background: The advent of ICIs has dramatically changed the treatment paradigm in mRCC. Although CN was demonstrated to improve survival in combination with cytokine-based therapies, its role is not well-defined in the ICI era. We aimed to compare survival outcomes of patients treated with ICIs, based on their CN status. Methods: The National Cancer Database was queried to identify all patients older than 18 years with mRCC who received ICIs from 2015 to 2018. Chi-Square and Mann-Whitney U tests were used to compare frequency distributions. Cox proportional hazards regression was employed for multivariate analysis of factors associated with overall survival (OS). Results: A total of 4,369 patients were identified- 36.4% (n=1589) had undergone CN. Among patients who got CN, 85.3% were treated with upfront surgery while 13.8% received prior systemic therapy ( P = 0.001). The study population was predominantly Caucasian (89.2%) and male (70.6%). Patients who underwent CN were younger (median age 61 vs. 65 years, P = <0.001). Large primary tumors and clinically node-negative status were associated with higher odds of CN (T4 disease - odds ratio (OR) for 1.49, 95% CI 1.13-3.44, P = 0.03; cN0 disease - OR 1.56, 95% CI 1.23-4.56, P = 0.04). OS after 1 year was significantly higher in patients who underwent CN (66.8% vs 33.2%. P <0.001). On multivariate analysis, CN was independently predictive of improved OS with a hazard ratio (HR) of 0.53 and 95% CI 0.41-0.68, P <0.001. Conclusions: In this large retrospective analysis, CN was associated with improved OS among patients with mRCC receiving ICI-based therapies. Our findings suggest that despite recent advances in systemic therapies for mRCC, CN retains an important role in carefully selected patients.[Table: see text]