Optimal duration of androgen deprivation therapy following radiation therapy in intermediate- or high-risk non-metastatic prostate cancer: A systematic review and meta-analysis

OBJECTIVES To investigate current evidence on the optimal duration of adjuvant hormone deprivation for prostate cancer treated with radiation therapy with curative intent. MATERIALS AND METHODS A systematic search was performed in electronic databases. Data from randomized trials comparing different durations of hormone blockade was collected for pooled analysis. Overall survival, disease-free survival, disease-specific survival and toxicity were the outcomes of interest. Meta-analyses were performed using random-effects model. RESULTS Six studies met the eligibility criteria. For overall survival, the pooled data from the studies demonstrated a statistically significant benefit for longer hormone deprivation (Hazard Ratio 0.84; 95% CI 0.74 - 0.96). A statistically significant benefit was also found for disease-free survival (Hazard Ratio 0.74; 95% CI 0.62 - 0.89), and disease-specific survival (Hazard Ratio 0.73; 95% CI 0.62 - 0.85). Studies with longer blockade duration arm demonstrated greater benefit. Toxicity was low, with no increase in cardiovascular events. CONCLUSIONS Longer duration of androgen deprivation combined to radiotherapy prolongs OS, DFS and DSS in patients with intermediate and high-risk non-metastatic prostate cancer. However, this evidence is based on trials using older radiation techniques, and further research of combination of androgen deprivation and new RT technologies may be warranted.