Targeted Therapy and Immunotherapy: Effect of Body Mass Index on Clinical Outcomes in Patients Diagnosed with Metastatic Renal Cell Carcinoma

Background: Previous research has identified an association between high body mass index (BMI) and better overall survival (OS) in metastatic renal cell carcinoma (mRCC) patients treated with vascular endothelial growth factor-tyrosine kinase inhibitors (VEGF-TKIs). Objective: The current study sought to determine whether the effect of BMI on OS extends beyond VEGF-TKIs to mTOR inhibitors or immunotherapy (IO). Design, Setting and Participants: A retrospective study was conducted among patients diagnosed with mRCC treated at a single institution from 2009 to 2017. Demographic and clinical variables were collected. BMI was characterized as high (≥25 kg/m2) versus low (<25 kg/m2). Outcomes Measurement and Statistical Analysis: The Kaplan-Meier method was used to estimate the difference in OS, with comparisons based on BMI and by treatment type. Results and Limitations: Among 353 patients (M = 64 years old, 73% male) 66% were overweight or obese (BMI ≥ 25 kg/m2). Patients were treated with VEGF-TKI (65%), mTOR (23%), or IO (12%). Among patients treated with VEGF-TKI with low BMI, median OS was 24.0 months (95% CI, 20.7–27.2) versus 36.0 months (95% CI, 18.6–53.3) among patients with high BMI (P = 0.02). The median OS for patients with low BMI treated with mTOR was 18.0 months (95% CI, 2.8–33.1), versus 25.0 months (95% CI, 16.6–33.4) among patients with high BMI (P = 0.04). In contrast, patients with low BMI treated with IO had a median OS of 23.6 months (95% CI, 17.5–29.7) versus 19.9 months (95% CI, 10.6–29.2) among patients with high BMI (P = 0.26). The retrospective nature and the small sample size are the main limitations of this study. Conclusions: High-BMI was associated with improved OS in patients with mRCC treated with VEGF-TKI and mTOR, but the inverse trend was observed among patients receiving IO. Our data highlight the need to reassess this phenomenon in the context of IO-based regimens.