Hormone Therapy: The First Treatment for Metastatic Prostate Cancer
Androgens are male hormones, and they are known to stimulate the growth of prostate cancer cells. Testosterone is a type of androgen made in the testicles, and accounts for the majority of androgens in the body. The rest of the body’s androgens are made in the adrenal glands, which are small glands that sit on top of the kidneys.
Hormone therapy for prostate cancer, also called androgen deprivation therapy, can slow the growth of cancer by lowering the level of androgens in the body. This is done by either stopping or lowering the production of androgens, or by preventing the androgens from acting on prostate cancer cells.
Hormone therapy is a primary treatment for stage 4 prostate cancer and includes the following options.
Orchiectomy
Orchiectomy is the surgical removal of the testicles, where most of the androgens are made. An orchiectomy usually does not require a hospital stay. Because its effects are permanent and irreversible, most men choose drug therapy.
Luteinizing Hormone-Releasing Hormone (LHRH) Agonists and Antagonists
LHRH agonists and antagonists are medications that block the production of androgens in the testicles. Therapy with these drugs is sometimes called medical castration because the testicles are not removed but hormone levels can become as low as they do with orchiectomy.
LHRH agonists and antagonists can be given as pills, shots, or implants under the skin, and, depending on the drug used, can be given anywhere from once a month to once a year. Unlike with orchiectomy, the effects of these drugs are reversible.
Four LHRH agonists are available in the United States to treat stage 4 prostate cancer:
Two LHRH antagonists are available in the United States to treat stage 4 prostate cancer:
Abiraterone (Zytiga)
Abiraterone helps stop the adrenal glands and prostate cancer cells from making androgens, and is given orally as a pill. Abiraterone doesn’t stop the testicles from making testosterone, so men who have not had an orchiectomy will also need to receive an LHRH agonist or antagonist at the same time.
Ketoconazole (Nizoral)
Ketoconazole blocks the production of androgens in the adrenal glands and is often used to lower testosterone quickly in men who were recently diagnosed with stage 4 prostate cancer. Ketoconazole is also used after other forms of hormone therapy have been ineffective. It’s taken orally as a pill.
Anti-Androgen Therapy
Anti-androgen therapy prevents androgens from acting on prostate cancer cells and causing tumor growth. These medications include:
They are taken daily as pills and may be used if other hormone therapies are no longer effective, or they may be combined with other hormone therapies for more aggressive treatment.
If the cancer progresses after hormone therapy, one or more of these drugs can be swapped out for others. “There is a possibility of resistance if you’ve taken one, but you do have more hormone therapy options than you did 15 years ago,” Dr. Dahut says.
“Today there is a greater intensification of treatment earlier on in the stage 4 cancer journey,” he adds. “Multiple studies show that you live longer if you receive more than the traditional hormonal therapy at the time of metastatic diagnosis.”
Common side effects of hormone therapy include low sex drive, erectile dysfuction, hot flashes, shrinkage of testicles and penis, anemia, and weakened bones. Other side effects include diarrhea, nausea, upset stomach, and itching.
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