Novel prognostic model of overall survival in patients undergoing cytoreductive nephrectomy: Importance of pretreatment clinical and serological parameters.

430 Background: Over the past decade, there has been an increasing interest in combining surgical and systemic therapy to combat metastatic renal cell carcinoma (mRCC) with upfront cytoreductive nephrectomy (CN) favored in well selected patients. This study presents a novel risk stratification model to identify those who may benefit from upfront CN within the current targeted therapy era. Methods: Eighty-two patients with mRCC who underwent CN within our tertiary care referral center were identified. Potential pre-operative clinical and serologic predictors of overall survival (OS) were evaluated using both univariate and multivariable Cox-Regression analyses. A Recursive Partitioning and Regression Tree (RPART) model was subsequently developed allowing for stratification of patients into risk groups on the basis of OS. Results: The derived RPART tree, was able to stratify patients into 4 risk groups ranging from “low risk” to “very high risk” with respect to their expected OS utilizing the number of meta...