How Does Hormone Therapy Treat Prostate Cancer?

Prostate cancer is a type of cancer that starts in the prostate gland. The prostate gland is a part of the reproductive system in men. It makes fluid that is part of semen. In the U.S., about 1 in 8 people with prostate glands will be diagnosed with prostate cancer at some point in their lives. 

There are many ways to treat prostate cancer. Treatment often includes surgery, radiation, and hormone therapy. Chemotherapy, immunotherapy, and targeted therapy are also possible options depending on your situation. 

Here, we’ll talk about hormone therapy medications — how they help treat prostate cancer, what medications are used, and what side effects are possible.

What is hormone therapy, and why is it used in prostate cancer?

Hormone therapy is a type of treatment that blocks or changes the effects of hormones in the body. Hormones like testosterone can cause prostate cancer to grow. 

Testosterone is mostly made in the testicles. Luteinizing hormone-releasing hormone (LHRH) and gonadotropin-releasing hormone (GnRH) are hormones made in the brain. These hormones tell the testicles when to make testosterone. 

Hormone therapy is also known as androgen deprivation therapy (ADT). It can stop the body from making testosterone. It can also block what testosterone does in the body. If the prostate cancer doesn’t have testosterone fueling it to grow, the tumor will likely shrink or grow more slowly for some time. Hormone therapy can slow prostate cancer’s growth, but it doesn’t cure it. 

Hormone therapy can lower testosterone in the body in two ways: surgically or with medications. Surgery involves removing the testes. This is called surgical castration. Hormone medications lower testosterone levels without surgery. This is called medical castration.

Hormone therapy is a key treatment strategy for many kinds of prostate cancer. It may be used:

• During or after treatment with radiation (if you have a high risk of prostate cancer coming back).

• If prostate cancer has come back after already being treated.

• If you have metastatic prostate cancer (prostate cancer that has spread outside of the prostate).

How fast does hormone therapy work?

Hormone therapy can work rather quickly to lower testosterone levels in the body. Testosterone levels usually drop within 2 to 4 weeks while using leuprolide (Lupron Depot). This is a common hormone therapy medication.

Degarelix (Firmagon) works even faster than leuprolide. This is another hormone therapy medication. In one study, it caused testosterone levels to drop by about 88% after 1 day. After 3 days, levels had dropped by 94%. After 28 days, levels dropped by 98%. 

In other words, timing varies by medication. But, as a rule of thumb, testosterone levels drop to a desired amount often within a month.

What are the different types of hormone therapy medications?

There are many different types of medications that can be used for hormone therapy in prostate cancer. The most common ones are LHRH agonists, LHRH antagonists, and antiandrogens. 

LHRH (luteinizing hormone-releasing hormone) agonists

LHRH agonists work by stopping the testicles from making testosterone. LHRH agonists are also known as GnRH agonists. LHRH agonists are available in multiple dosage forms and dosing schedules that can accommodate your preferences.

• Goserelin (Zoladex): This is an under-the-skin (subcutaneous) injection that can be given every 4 to 12 weeks (1 to 3 months).

• Leuprolide (Lupron, Eligard): This is an injection that can be given into the muscle (IM) or under the skin. It can be given every month, every 3 months, every 4 months, or every 6 months. 

• Leuprolide mesylate (Camcevi): This is an under-the-skin injection that’s given every 6 months. 

• Triptorelin (Trelstar): This is an IM injection that can be given every 1 month, every 3 months, or every 6 months. 

• Histrelin (Vantas): This is an implant placed beneath the skin. It’s usually replaced after 1 year (12 months). 

One downside of these medications is that they can cause a testosterone flare. This is when testosterone levels temporarily go up before they eventually go down. This can lead to unwanted side effects. People typically take antiandrogen medications to help block this testosterone flare — this is discussed more below.

LHRH (luteinizing hormone-releasing hormone) antagonists

LHRH antagonists are an alternative to LHRH agonists. LHRH antagonists work slightly differently: They stop the pituitary gland from making LHRH. This causes the testicles to stop making testosterone. These medications include: 

• Degarelix (Firmagon): This is an under-the-skin injection that’s given about once a month. 

• Relugolix (Orgovyx): This is an oral pill typically taken once daily. 

One advantage of LHRH antagonists over LHRH agonists is how quickly LHRH antagonists can lower testosterone levels without causing a testosterone flare. Low amounts of testosterone are usually seen within 7 days or less.

One disadvantage is that degarelix is a monthly injection. Compared to LHRH agonists, this is given more frequently.

Antiandrogens

Antiandrogens work by blocking receptors (chemical binding sites) on prostate cancer cells from testosterone that’s made in the body. Several antiandrogen medications are available:

• Flutamide (Eulexin) 

• Bicalutamide (Casodex) 

• Nilutamide (Nilandron) 

• Enzalutamide (Xtandi)

• Apalutamide (Erleada)

• Darolutamide (Nubeqa)

These medications are all oral pills. Depending on the medication, they may be taken 1 to 3 times daily. Some antiandrogen medications are also newer than others. Enzalutamide, apalutamide, and darolutamide are newer antiandrogens.

Antiandrogen medications are often started around the same time as starting an LHRH agonist medication. This combination helps lower the risk of experiencing testosterone flare symptoms. 

Testosterone flare caused by a LHRH agonist is thought to be caused by an initial increase of luteinizing hormone (LH). Testosterone flare symptoms often consist of bone pain or urinary pain. This flare reaction usually goes away after 2 weeks.

Even though symptoms typically go away, they can be unpleasant. For this reason, antiandrogens are usually used for a few weeks after starting an LHRH agonist.

Are certain antiandrogens preferred over others?

There isn’t one best antiandrogen. The best choice depends on your situation. This is also true for LHRH agonists and LHRH antagonists. 

But there are certain situations where newer antiandrogens may be preferred over older ones. This is often the case for people with prostate cancer that are no longer responding to initial hormonal therapies. For example, enzalutamide can be used for metastatic prostate cancer that may or may not still be responding to hormonal therapies. 

How effective are these medications? 

Hormone therapy usually works well for prostate cancer for a period of time — usually a few years. In general, both LHRH agonists and LHRH antagonists work well to lower testosterone levels over time. 

For example, leuprolide is shown to keep testosterone levels low for at least 6 months in about 93% of people who receive the medication every 6 months. 

For another example, in a study of over 600 people with advanced prostate cancer, degarelix was similar to leuprolide in lowering testosterone levels for up to one year.

There aren’t any direct studies that compare LHRH agonists to each other. But a recent study found that there’s no difference in effectiveness or side effects between triptorelin, histrelin, leuprolide, and goserelin. These are all LHRH agonists. 

Overall, the choice between these medications is usually made based on cost, preferred dosing schedule, and healthcare provider preference. 

Unfortunately, people may stop responding to hormone therapy treatments. This is called hormone-resistant (or castration-resistant) prostate cancer, also known as CRPC. Other treatments are usually used for CRPC.

What are common side effects of hormone therapy?

Hormone therapy can have many side effects. The longer you take hormone therapy, the greater your risk for side effects. This includes thinning bones (osteoporosis), weight gain, and heart disease. Your healthcare provider may recommend taking calcium and vitamin D3 supplements. This can support bone health while on hormone therapy for prostate cancer.

Other side effects of hormone therapy can include:

• Erectile dysfunction

• Weight gain

• Fatigue

• Loss of muscle mass

• Depression or mood swings

In general, hormone therapy may lower your desire for sex and can cause erectile dysfunction (ED). Luckily, there are ways to manage this side effect. You can read more about medications for ED here.

Why trust our experts?

Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Our editorial standards

Meet our experts