Long-term outcomes of combined androgen blockade therapy in stage IV prostate cancer

To clarify which subset of stage IV prostate cancer patients benefit from combined androgen blockade (CAB) using Japanese nationwide database. A total of 3,752 patients with stage IV disease from the prospective nationwide cohort database of the Japan Study Group of Prostate Cancer (J-CaP) were enrolled. All patients started primary androgen deprivation therapy (PADT) between 2001 and 2003, and the present study was performed using the data set from December 2011. Patients were divided into two groups according to initial treatments: CAB with luteinizing hormone-releasing hormone agonist (LHRH) plus anti-androgen (AA) and non-CAB treatments such as LHRH monotherapy. The overall survival (OS) and cancer-specific survival (CSS) for each group were estimated by the Kaplan-Meier method. A total of 2,967 patients (79.1 %) received CAB. Overall, no significant difference was observed in OS and CSS between the CAB group and the non-CAB group. However, CAB resulted in significantly better OS and CSS compared to non-CAB in patients with very high Japan Cancer of the Prostate Risk Assessment (J-CAPRA) scores of ten or greater (P = 0.007 and 0.013, respectively). Multivariate analysis revealed that CAB was an independent predictive factor for better OS (P = 0.013, hazard ratio = 0.83). Based on large-scale nationwide database, as PADT for prostate cancer patients with very high-risk disease, CAB resulted in better OS than other endocrine treatments.