Efficacy and Safety of Combined Androgen Blockade with Antiandrogen for Advanced Prostate Cancer

Background: Combined androgen blockade (CAB) is a promising treatment modality for prostate cancer (PCA). In the present meta-analysis, we compared the efficacy and safety of first-line CAB using an antiandrogen (AA) with castration monotherapy in patients with advanced PCA. Methods: PubMed, embase, Cochrane, and Google Scholar were searched for randomized controlled trials (RCTS) published through 12 December 2016. Hazard ratios (HRS) with 95% confidence intervals (CIS) were determined for primary outcomes: overall survival (OS) and progression-free survival (PFS). Subgroup analyses were performed for Western compared with Eastern patients and use of a nonsteroidal AA (NSAA) compared with a steroidal AA (SAA). Results: Compared with castration monotherapy, CAB using an AA was associated with significantly improved OS (n = 14; HR: 0.90; 95% CI: 0.84 to 0.97; p = 0.003) and PFS (n = 13; HR: 0.89; 95% CI: 0.80 to 1.00; p = 0.04). No significant difference in OS (p = 0.71) and PFS (p = 0.49) was observed between the Western and Eastern patients. Compared with castration monotherapy, CAB using a NSAA was associated with significantly improved OS (HR: 0.88; 95% CI: 0.82 to 0.95; p = 0.0009) and PFS (HR: 0.85; 95% CI: 0.73 to 0.98; p = 0.007)—a result that was not achieved with CAB using a SAA. The safety profiles of CAB and monotherapy were similar in terms of adverse events, including hot flushes, impotence, and grade 3 or 4 events, with the exception of risk of diarrhea and liver dysfunction or elevation in liver enzymes, which were statistically greater with CAB using an AA. Conclusions: Compared with castration monotherapy, first-line CAB therapy with an AA, especially a NSAA, resulted in significantly improved OS and PFS, and had an acceptable safety profile in patients with advanced PCA.