Duration of androgen deprivation therapy in high risk prostate cancer: Final results of a randomized phase III trial.

5008 Background: Long-term androgen deprivation therapy (ADT) combined with radiotherapy (RT) is a standard treatment for patients with high-risk prostate cancer (HRPC). However, the optimal duration of ADT is not yet defined. The aim of this randomized trial (Clinical Trials.gov, #NCT00223171) was to compare outcomes of RT combined with either 36 or 18 months of ADT. Methods: Patients with HRPC were randomized to pelvic and prostate RT combined with 36 (arm 1) or 18 months (arm 2) of ADT. Overall survival (OS) and quality of life (QoL) were primary end points. OS rates were compared with Cox Regression model and QoL data were analyzed through mixed linear model. Results: 630 patients were randomized, 310 to arm 1 and 320 to arm 2. With a median follow-up of 9.4 years, 290 patients had died (147 arm 1 vs. 143 arm 2). The 10-year OS rate was 62.4% (95% confidence interval [CI] 56.4%, 67.8%) for arm 1 and 62.0% (95% CI 56.1%, 67.3%) for arm 2 (p = 0.8412) with a global hazard ratio (HR) of 1.024 (95% CI 0.813-1.289, p = 0.8411). QoL analysis showed a significant difference (p < 0.001) in 6 scales and 13 items favoring 18 months ADT with two of them presenting a clinically relevant difference in mean scores of ≥10 points. Conclusions: In HRPC, ADT combined with RT can be safely reduced from 36 to 18 months without compromising outcomes or QoL. 18 months of ADT represents a new standard of care in HRPC. Funded by AstraZeneca Pharmaceuticals Clinical trial information: NCT00223171.