Long-term androgen-deprivation therapy (ADT) is the standard of care in combination with radiotherapy (RT) in high-risk prostate cancer (PC), despite substantial toxicity from the resulting hypogonadism. We hypothesized that a combination of more potent but shorter-term androgen inhibition in men with intermediate or high-risk localized PC would synergize with definitive RT to provide short-term testosterone recovery and improve disease control.
This prospective phase 2 single arm trial enrolled men with low volume unfavorable intermediate or high-risk localized PC. Treatment included 6 months of ADT concurrent with abiraterone acetate plus prednisone once daily (AAP) and RT to prostate and seminal vesicles. The primary endpoint was the proportion of men with an undetectable PSA at 12-months; secondary objectives included biochemical progression-free survival (PFS), testosterone recovery, toxicity, and sexual/ hormonal quality-of-life.
We enrolled 37 men between January 2014 and August 2016, 45% of whom were high-risk .All patients had T1-2 disease and PSAs G4 toxicities. The rate of undetectable PSA at 12-months was 55% (95% CI 36-72%). With 46 months median follow-up, two of 37 patients developed PSA progression (36-month PFS 96%; 95% CI: 76%, 99%), and 81% of patients recovered testosterone with median time to recovery 9.2 months. Hormonal/sexual function declined at six months with subsequent improvement by 24 months.
The combination of RT and 6 months of ADT and AAP demonstrated acceptable toxicity and a high rate of testosterone recovery with restoration of QOL and excellent disease control in men with low volume intermediate or high-risk localized prostate cancer. Prospective comparative studies are justified.

Copyright © 2020. Published by Elsevier Inc.