Hormone therapy is a way of treating prostate cancer by cutting off the supply of androgens, or male sex hormones, that cancer cells need to grow.
This treatment is also called androgen deprivation therapy (ADT), androgen suppression therapy, or testosterone depleting therapy.
Hormone therapy is often used to treat advanced prostate cancer, which is cancer that has spread to other parts of your body or that has come back after treatment. While it won’t cure this type of cancer, hormone therapy can slow down its growth.
What Are Androgens?
Everyone’s bodies make these hormones, but you’ll have more of them if you’re assigned male at birth. The most common androgens are testosterone and dihydrotestosterone.
Androgens work in many different ways in your body, including increasing your amount of red blood cells and building strong bones and muscles. But their main job is sexual development. They give men things like a deeper voice and facial hair, and they fuel the growth of prostate cells.
Testosterone is mainly made by your testicles, but your adrenal glands make a small amount, and sometimes even prostate cancer cells can, too. Some testosterone gets changed into dihydrotestosterone inside your testicles, prostate gland, and adrenal glands.
Hormones that come from your brain control the process. When androgen levels are low, a part of your brain called the hypothalamus releases a chemical called luteinizing hormone-releasing hormone (LHRH). That signals the nearby pituitary gland to make luteinizing hormone (LH), which, in men, stimulates your testicles to make testosterone.
How Does Hormone Therapy Work?
Both healthy cells and cancer cells in your prostate need androgens to grow. The most common type of hormone therapy treats prostate cancer by blocking your body from making these hormones. Other treatments keep cancer cells from using androgens as fuel.
At first, hormone therapy is usually able to stop prostate cancer from growing. This type of cancer is described as androgen dependent, androgen sensitive, castration sensitive, or hormone sensitive. It’s hard to know how long hormone therapy will control your prostate cancer, but it can be for years.
As time goes on, prostate cancer is usually able to grow even when your androgen levels are very low. This type is called castration resistant. At that point, you may need to switch to a different type of hormone therapy or try a different treatment altogether.
While you’re getting hormone therapy, you’ll have blood tests from time to time to test your level of prostate-specific antigen (PSA). PSA is a protein made by both healthy and cancerous prostate cells. Your level usually drops after you start hormone therapy. If it’s rising quickly, that could mean that the medication you’ve been taking is no longer working, and the cancer has come back or is growing.
Who Gets Hormone Therapy for Prostate Cancer?
Hormone therapy is used in several situations. It’s the main treatment for controlling advanced prostate cancer. It’s also offered when lab and imaging tests show that your cancer is likely to grow and spread. Doctors may recommend hormone therapy:
- Along with radiation therapy to shrink a tumor and make it easier to treat
- To try to keep the cancer from coming back after other treatment
- When prostate cancer has spread to other parts of your body
- When prostate cancer has come back after other treatment
- To ease symptoms if you can’t have other treatment
Types of Hormone Therapy
The most common type of hormone therapy used to treat prostate cancer stops your testicles from making testosterone. This can be done in several ways:
LHRH agonists. These drugs are an imitation form of LHRH that keeps your brain from releasing it naturally. Your pituitary gland stops responding, so it no longer makes LH, and your testicles don’t get the message to make testosterone. Examples include:
- Goserelin (Zoladex)
- Leuprolide (Camcevi, Eligard, Lupron Depot)
- Triptorelin (Trelstar)
LHRH antagonists. These drugs block the action of your natural LHRH by keeping the hormone from connecting to receptors in your pituitary gland. Examples include:
- Degarelix (Firmagon)
- Relugolix (Orgovyx)
Surgery. A procedure called an orchiectomy removes your testicles and reduces testosterone levels.
CYP17 inhibitors. Because some tissues besides your testicles can make small amounts of testosterone, you might get a type of drug that stops production of the hormone in other places in your body. That’s done by blocking the action of an enzyme – CYP17 – that’s needed for this process. These drugs are also called androgen synthesis inhibitors. Medications used for this include:
- Abiraterone (Yonsa, Zytiga)
- Ketoconazole
Some research has found that abiraterone may work better to lower PSA levels in Black men than in White men, and could help them live longer. But Black men are less likely than White men to get this drug or other newer hormone therapy medications.
Antiandrogens. A different type of hormone therapy keeps androgens from reaching prostate cancer cells. This is done with drugs called antiandrogens, androgen receptor blockers, or androgen receptor antagonists. They include:
- Apalutamide (Erleada)
- Bicalutamide (Casodex)
- Darolutamide (Nubeqa)
- Enzalutamide (Xtandi)
- Flutamide (Eulexin)
- Nilutamide (Nilandron)
In many cases, doctors recommend a combination approach. You’ll get either an orchiectomy or medication to stop testosterone production, plus a medication to keep any remaining androgens from working.
How Hormone Therapy for Prostate Cancer Is Given
Some hormone therapy drugs are pills you take every day. Others you get as a shot, either every month or every few months, or as a small pellet implanted under the skin in your belly.
Surgery to remove your testicles can’t be reversed. But with medication-based hormone therapy, your body usually goes back to making androgens if you stop taking the drugs.
You might take hormone therapy all the time, or you might have treatment off and on. Those two approaches are called continuous and intermittent therapy.
Continuous therapy. You’ll take medication for the rest of your life or until it stops working. Your body would have reduced androgen production.
Intermittent therapy. You’ll start and stop hormone therapy, allowing your body to make androgens again between treatment periods. This might be done on a set schedule, such as several months on then several months off. Or you could wait to restart medication until your PSA levels start rising. This gives you a break from side effects.
Those side effects can be very uncomfortable and affect your quality of life. They usually come from the loss of testosterone in your body. While they’re different for each drug and for each person, common symptoms include:
- Sexual side effects, including loss of interest in sex and erectile dysfunction
- Hot flashes
- Enlarged or sore breasts
- Bone thinning and fractures
- Diarrhea
- Fatigue
- Moodiness and depression
- Increased risk of heart disease, high cholesterol, diabetes, and anemia
There’s no scientific agreement on whether continuous or intermittent therapy is best, so talk to your doctor about the pros and cons of each.
Another issue to discuss with your doctor is the best time to start hormone therapy. You could wait to take medication until you’re having symptoms. Or you could begin as soon as you’re either diagnosed with advanced prostate cancer or your PSA levels rise after other treatment. Studies are being done about which approach works best.
Show Sources
Photo Credit: Westend61/Getty Images
SOURCES:
Urology Care Foundation: “Hormone Therapy,” “What is Advanced Prostate Cancer?”
American Cancer Society: “Hormone Therapy for Prostate Cancer,” “Screening Tests for Prostate Cancer,” “Following PSA Levels During and After Prostate Cancer Treatment,” “Initial Treatment of Prostate Cancer, by Stage and Risk Group.”
Johns Hopkins Medicine: “Hormone Therapy for Prostate Cancer.”
Cleveland Clinic: “Androgens.”
National Cancer Institute: “Hormone Therapy for Prostate Cancer,” “Dihydrotestosterone.”
Endocrine Reviews: “Hormonal Therapy for Prostate Cancer.”
BMC Cancer: “A review of new hormonal therapies for prostate cancer in black men: is there enough data?”
JAMA Network Open: “Racial and Ethnic Disparities in Use of Novel Hormonal Therapy Agents in Patients With Prostate Cancer.”
The Journals of Gerontology: “Testosterone Induces Erythrocytosis via Increased Erythropoietin and Suppressed Hepcidin: Evidence for a New Erythropoietin/Hemoglobin Set Point.”
Prostate Cancer UK: “How does hormone therapy work?”
The New England Journal of Medicine: “Intermittent versus continuous androgen deprivation in prostate cancer.”
Nature Reviews Urology: “Intermittent versus continuous androgen deprivation therapy for advanced prostate cancer.”
