Body Mass Index and Survival in a Prospective Randomized Trial of Localized High-Risk Renal Cell Carcinoma.

Background: The relationship between adiposity and renal cell carcinoma is poorly understood. Prior studies have suggested body mass index (BMI) may be associated with indolent disease.

Methods: We reviewed the clinicopathologic records of 845 patients across 14 countries who were enrolled in a prospective, placebo-controlled study of adjuvant girentuximab treatment for high-risk renal cell carcinoma. Clinical features analyzed included age, gender, race, BMI, and performance status. BMI was stratified into <25 kg/m(2), 25.0-29.9 kg/m(2), 30.0-34.9 kg/m(2), and ≥35 kg/m(2) We examined the association of BMI with stage and survival using logistic and Cox regression analyses, respectively.

Results: 845 patients were included for analysis. The majority (72%) were overweight/obese. There was an inverse relationship between BMI and lymph node involvement (P = 0.04). Obesity was associated with improved disease-free and overall survival (log rank <0.01 for both). When compared with normal weight subjects, those with a BMI 30-34.9 [HR 0.50; 95% confidence interval (CI) 0.31-0.81] and BMI ≥35 (HR 0.24; 95% CI 0.09-0.60) had significantly improved overall survival. A trend towards improved disease-free survival was found among subjects with BMI 30-34.9 (HR 0.77; 95% CI 0.56-1.05) and ≥35 (HR 0.74; 95% CI, 0.48-1.15).

Conclusions: In a prospective cohort of nephrectomized patients with high-risk disease, obesity is associated with lower risk of lymphatic spread and improved overall survival.

Impact: This is the first study utilizing data from a prospective randomized trial reporting an association between obesity and improved overall survival for patients with clear cell renal cell carcinoma. Cancer Epidemiol Biomarkers Prev; 25(9); 1326-32. ©2016 AACR.