Hormone therapy for prostate cancer is also known as androgen deprivation therapy (ADT). Prostate cancer cannot grow or survive without androgens, which include testosterone and other male hormones. Hormone therapy decreases the amount of androgens in a man's body. Reducing androgens can slow the growth of the cancer and even shrink the tumor.
Hormone therapy may be used along with radiation treatment when there is a high risk of the cancer returning. Or hormone therapy may be used after surgery or radiation if any cancer remains.
Prostate cancer is a complex disease. Doctors cannot always predict how fast or slow it will grow. Nor do they agree on when to treat it, or which treatments to use. Predicting and monitoring the disease with accuracy help doctors and patients make decisions that result in the best survival rates and quality of life.
Hormone therapy may also help men who have cancer that has spread and who cannot have surgery or radiation. It may be used when prostate cancer has spread outside the prostate (metastatic disease). In these cases, hormone therapy reduces pain and helps men live a little longer.1
Hormone therapy may be used to suppress prostate cancer cells, which is reflected in lower levels of prostate-specific antigen (PSA).
Hormone therapy alone is sometimes used as the main treatment for prostate cancer in men who can't have surgery or radiation. But hormone therapy doesn't seem to help men ages 66 and older who have localized prostate cancer. These men live just as long with active surveillance.2
Taking medicine, such as luteinizing hormone-releasing hormone (LHRH) medicine, is one way to reduce androgens. Another way, used much less often, is surgery to remove the testicles, also known as an orchiectomy.
LHRH antagonists. These drugs stop the body from making testosterone. They work right away. And they avoid the flare caused by LHRH agonists, which can make symptoms worse for several weeks. One LHRH antagonist is degarelix (Firmagon).
Androgen inhibitors. These are medicines that block enzymes that the body needs to make testosterone. They include enzalutamide (Xtandi), ketoconazole, and abiraterone (Zytiga), which is given along with prednisone.
Antiandrogens. These drugs often are used along with LHRH agonists. Antiandrogens help block the body's supply of testosterone. There are steroidal antiandrogens and "pure" antiandrogens. The steroidal antiandrogens include megestrol (Megace). The "pure" or nonsteroidal antiandrogens include bicalutamide (Casodex), flutamide, and nilutamide (Nilandron).
Orchiectomy. This surgery is considered to be hormone therapy. This is because removing the testicles, where more than 90% of the body's androgens are made, decreases testosterone levels. Removing the testicles may be the simplest way to reduce androgen levels, but it is permanent.
Sometimes androgen deprivation (orchiectomy or an LHRH agonist) and an antiandrogen are used together for treatment. This targets the testosterone made by the testicles and the adrenal glands. It is called a combined androgen blockade (CAB).
Other hormone therapies may include the use of medicines such as megestrol, estrogen, aminoglutethimide combined with hydrocortisone, and corticosteroids (prednisone, dexamethasone, and hydrocortisone).