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.