Prostate cancer is the second most common cancer in men representing approximately 30% of all cancers diagnosed in men. When confined to the prostate gland the disease is curable with local therapy. However approximately 50% of men fail local therapy and develop incurable metastatic disease. Androgen deprivation (AD) therapy remains the mainstay of treatment, not only for advanced disease but also in the adjuvant and neo-adjuvant settings. Androgen deprivation therapy induces a remission in 80 to 90% of patients with advanced disease and results in a median progression-free survival of 12 to 33 months, at which time an androgen-independent phenotype usually emerges. This accounts for the median overall survival of 23 to 37 months from the initiation of androgen deprivation.