Recurrent prostate cancer after radical radiation therapy is a common problem with often a long interval from biochemical failure to the time of symptomatic relapse. Androgen deprivation therapy (ADT) is the most commonly used intervention following radiation failure and currently is often started immediately after the recognition of biochemical failure in the absence of symptoms. ADT is associated with side effects that can impact on quality of life. It is unclear whether ADT reduces prostate-specific mortality. There is currently insufficient evidence on the timing of ADT with respect to prevention of prostate cancer death and quality of life and cost particularly for men with fast and slow prostate specific antigen (PSA) doubling times.