Prognostic impact of sarcopenia in patients with metastatic hormone-sensitive prostate cancer

Background: Cancer cachexia is associated with a poor prognosis. This study aimed to investigate the association between sarcopenia and survival in patients with metastatic hormone-sensitive prostate cancer. Methods: We retrospectively evaluated 197 patients diagnosed with metastatic hormone-sensitive prostate cancer in our department and its affiliated institution between January 2008 and December 2015. Sarcopenia was diagnosed according to the sex-specific consensus definition. Castration-resistance prostate cancer-free survival, cancer-specific survival and overall survival from the metastatic hormone-sensitive prostate cancer diagnoses were calculated using the Kaplan-Meier method and compared using the log-rank test. Risk factors affecting the survival outcomes were analyzed using the Cox proportional regression analysis. Results: In total, 163 patients (82.7%) had sarcopenia. Cancer-specific survival and overall survival were significantly shorter in sarcopenic patients than in non-sarcopenic patients (median cancer-specific survival: 77.0 months vs. not reached, P = 0.0099; overall survival: 72.0 months vs. not reached, P = 0.0465), whereas castration-resistance prostate cancer-free survival did not significantly differ between the groups (P = 0.6063). Multivariate analyses showed that sarcopenia was an independent factor for cancer-specific survival (hazard ratio: 2.18, P = 0.0451), together with the Gleason score (hazard ratio: 1.87, P = 0.0272) and LATITUDE risk classification (hazard ratio: 2.73, P = 0.0008). Moreover, the prognostic association of sarcopenia was remarkable in patients aged <73.0 years (cancer-specific survival: 82.0 months vs. not reached, P = 0.0027; overall survival: 72.0 months vs. not reached, P = 0.0078 in sarcopenic vs. non-sarcopenic patients), whereas the association was not significant in patients aged >= 73.0 years (cancer-specific survival: 76.0 and 75.0 months, respectively, P = 0.7879; overall survival: 67.0 and 52.0 months, respectively, P = 0.7263). Conclusion: Sarcopenia was an independent risk factor of cancer-specific survival in patients with metastatic hormone-sensitive prostate cancer, especially in younger patients.