Hormone therapy for prostate cancer is treatment to stop the male hormone testosterone from reaching the prostate cancer cells in your body. Hormone therapy for prostate cancer is also called androgen deprivation therapy.Most prostate cancer cells rely on testosterone to help them grow. Hormone therapy for prostate cancer cuts off the supply of testosterone or stops testosterone from reaching the cancer cells, causing cancer cells to die or to grow more slowly.Hormone therapy for prostate cancer may involve medications, or it can involve surgery to remove the testicles.