Metformin (met) use and outcome of sunitinib (Su) treatment (tx) in diabetic patients (pts) with metastatic renal cell carcinoma (mRCC).

e15618 Background: Su is a standard tx for mRCC. Pre-clinical and clinical studies in several cancer types suggest that the antidiabetic agent Met has antitumor activity. Met may negatively regulate mTOR activity. Its effect on the outcome of targeted therapies in mRCC is poorly defined. We analyzed the effect of Met use on the outcome sunitinib tx in diabetic pts with mRCC. Methods: We performed a retrospective study of an unselected cohort of diabetic pts with mRCC, who were treated with Su in 7 centers across 2 countries. Pts were divided into 2 groups: (1) Met users and (2) Met naive. The effect of Met use on response rate (RR), progression free survival (PFS) and overall survival (OS), was tested with adjustment of other known confounding risk factors using a chisquare test and partial likelihood test from cox model. Furthermore, univariate and multivariate analyses of association between clinicopathologic factors and Met use, and outcome were performed using the entire pt cohort. Results: Between 20...