Body Mass Index and Metastatic Renal Cell Carcinoma: Clinical and Biological Correlations.

PurposeObesity is an established risk factor for clear cell renal cell carcinoma (RCC); however, some reports suggest that RCC developing in obese patients may be more indolent. We investigated the clinical and biologic effect of body mass index (BMI) on treatment outcomes in patients with metastatic RCC.MethodsThe impact of BMI (high BMI: ≥ 25 kg/m2 v low BMI: < 25 kg/m2) on overall survival (OS) and treatment outcome with targeted therapy was investigated in 1,975 patients from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) and in an external validation cohort of 4,657 patients. Gene expression profiling focusing on fatty acid metabolism pathway, in The Cancer Genome Atlas data set, and immunohistochemistry staining for fatty acid synthase (FASN) were also investigated. Cox regression was undertaken to estimate the association of BMI with OS, adjusted for the IMDC prognostic factors.ResultsIn the IMDC cohort, median OS was 25.6 months (95% CI, 23.2 to 28.6) in patients with...