MP37-07 ASSOCIATION OF SARCOPENIA VERSUS OBESITY WITH SURVIVAL IN METASTATIC OR CASTRATE-RESISTANT PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVE: The complex interplay between metabolic factors, body composition, and disease-specific outcomes in men with prostate cancer is poorly understood. Obesity (BMI ≥30kg/m2) is associated with a greater risk of having high-risk and advanced prostate cancer at diagnosis, but is also associated with better overall survival (OS) in metastatic disease. Conversely, sarcopenia (muscle mass <550mm2/m2) is associated with shorter OS and noncancer death in men with metastatic prostate cancer. This study seeks to evaluate whether sarcopenia, rather than obesity, is associated with overall survival in men with metastatic or castrateresistant prostate cancer (mPC/CRPC). METHODS: We performed a retrospective electronic medical record review of all men with mPC/CRPC and a CT of the abdomen and pelvis presenting to the Vanderbilt Comprehensive Prostate Cancer Clinic from 2012-2017. Demographic, pathologic, and survival information were obtained per IRB-protocol. Muscle mass was calculated by measuring the cross-sectional area of the psoas muscle at the L3 vertebrae and normalized to patient height. OS was estimated using the Kaplan-Meier method and compared with log-rank tests. Multivariate analyses using Cox proportional hazard models were performed adjusting for age, Charlson comorbidity index, race, and prostate cancer stage at presentation. RESULTS: 182 men (mean age 70.7 years) were included in the analysis. Sarcopenia with muscle mass <550 mm2/m2 was present in 40.6% (N=64) and obesity with BMI ≥30 was present in 60.3% (N=68) of men. Sarcopenia was associated with worse overall survival (HR 7.13, p = 0.008) and obesity was associated with better overall survival (HR 5.02, p = 0.025) over a mean 3.18 years of follow up. Higher muscle mass (HR 0.998, p = 0.032) was a significant predictor of longer overall survival, and increasing age (HR 1.03, p = 0.039) was a significant predictor of shorter overall survival on multivariate analysis. CONCLUSIONS: In men with advanced prostate cancer, both obesity and sarcopenia are associated with OS. Muscle mass is an independent predictor of better OS in men with metastatic or castrateresistant prostate cancer. (Figure Presented).