High subcutaneous adipose tissue predicts the prognosis in metastatic castration-resistant prostate cancer patients in post chemotherapy setting

Background Cancer studies have shown that body mass index (BMI), skeletal muscle mass (SMM) and adipose tissue indexes are linked to overall survival (OS) and progression-free survival (PFS). New treatments (abiraterone acetate, enzalutamide cabazitaxel, radium-223, sipuleucel-T) have improved patient outcomes in metastatic castration-resistant prostate cancer (mCRPC). Our objective was to analyse whether body composition parameters exert a prognostic role in mCRPC patients treated with next generation of androgen receptor (AR) axis inhibitors (abiraterone and enzalutamide). Methods All mCRPC patients from our institution who were enrolled in two prospective trials, assessing the efficacy of abiraterone acetate and the efficacy of enzalutamide, were selected. SMM, visceral and subcutaneous adipose tissue (SAT) indexes were assessed with computed tomography imaging by measuring cross-sectional areas of the tissues. Results In the 120 patients with available data, median OS and PFS were respectively: 16 months (95% confidence interval [CI] = 12-19) and 4 months (95% [CI] = 3-6). OS was associated with the SAT index: median survival was 15 months (95% [CI] 9-18) for patients with a SAT index < median value and 18 months (95% [CI] 13-30) for patients with a SAT index above (P = 0.008). In multivariate analyses, only the occurrence of visceral metastasis (P = 0.004), pain (P = 0.015) and SAT index (P = 0.036) were statistically significant predictors of OS. From baseline to 3 months, the SMM index loss was 2.49 ± 0.44 cm²/m² (P < 0.001) corresponding to nearly 3.4 kg of muscle loss. Conclusions High volume of SAT is independently associated with overall survival in mCRPC patients treated with next generation AR axis inhibitors.