Treating Prostate Cancer With Hormone Therapy

“The overwhelming majority of patients get androgen deprivation by way of medical therapy,” explains Moshe Ornstein, MD, a genitourinary medical oncologist at the Cleveland Clinic.

Doctors use several types of medication to lower testosterone levels, but these therapies do so only temporarily. When you stop taking them, testosterone levels begin to rise again.

Here are some of the most commonly used hormone therapies.

Luteinizing Hormone-Releasing Hormone (LHRH) Agonists and Antagonists

LHRH is one of the key hormones released by the body before testosterone is produced. LHRH agonists and antagonists lower testosterone levels by blocking the release of LHRH. Treatment with these drugs is sometimes called medical castration because they lower androgen levels as much as orchiectomy, or removal of the testicles, does. (2)

LHRH agonists and antagonists include:

CYP17 Inhibitors

An LHRH agonist or antagonist can stop the testicles from making androgens, but other cells in the body (including prostate cancer cells) still make small amounts of androgens. These small amounts of hormones can continue to stimulate cancer growth. The medication abiraterone (Zytiga) blocks a key enzyme involved in androgen production called the CYP17 enzyme. Zytiga can be used to treat metastatic prostate cancer that has become resistant to traditional hormone therapies. (3)

Anti-Androgens

For most prostate cancer cells to grow, androgens have to attach to a protein in the prostate cancer cell called an androgen receptor. Anti-androgens are drugs that also connect to these receptors. “The testosterone can’t hit its target because there is something already there,” explains Mark Pomerantz, MD, a medical oncologist at the Dana-Farber Cancer Institute in Boston.

Traditional anti-androgens may be given along with LHRH agonists and antagonists. They include:

Doctors now have access to a newer type of anti-androgen that interferes with androgen function even more effectively. “These newer agents bind to the androgen receptor much more tightly and also seem to break up the androgen receptor,” explains Dr. Pomerantz. They may be used along with an LHRH agonist or antagonist as a first-line hormonal therapy or added later if traditional hormone treatments are not working.

Next-generation anti-androgens include:

RELATED: Prostate Cancer Treatment Options