Hormone Therapy for Prostate Cancer: What is it and When is it Used?

Hormone therapy is sometimes referred to as androgen suppression therapy because it aims to lower androgens, the male hormones that can stimulate prostate cancer growth. It is sometimes used by itself or in combination with other treatments such as radiation or surgery.

Androgens are primarily produced in the testicles, but can also be made in the adrenal glands (which are located above the kidneys), as well as the prostate itself. Besides testosterone, dihydrotestosterone (DHT) is another common androgen that can be targeted with hormone therapy.

By decreasing the levels of hormones which activate the prostate, or by blocking them from interacting with prostate cells, hormone therapy can slow the growth and activity of prostate cancer cells. Unlike chemotherapy, radiation, or surgery it does not kill the prostate cancer or remove it. Rather, the goal is to shrink the cancer cells or make them grow more slowly.

While it they are not a cure, Dr. David Wise, a medical oncologist at NYU Langone Health, noted that hormonal therapies  lower the cancer burden in 99.9% of people.

When is hormone therapy used?

Based on a series of medical tests, prostate cancer is classified into three types:

• Localized: the cancer is confined to the prostate
• Regional: the cancer has spread to nearby areas and a lymph node is involved
• Metastatic: the cancer has spread to distant parts of the body

This classification helps in deciding the most effective treatment approach.

If, for example, the disease is localized it will be placed in a low, medium or high risk group. Treatment recommendations depend on the risk group assigned, as well as overall health and treatment goals. Recommendations also vary for regional and metastatic disease.

If you have a more aggressive localized disease:

• Doctors often recommend hormone therapy in combination with radiation therapy.
• If you have surgery to remove the prostate, doctors may use hormone therapy afterwards to address high-risk features found during surgery or if a blood test shows your PSA (prostate-specific antigen) levels rise post-surgery. In this situation, hormone therapy is often used in combination with radiation.
• When your life expectancy is shorter based on other health problems, hormone therapy alone may be used to slow disease progression.

If you have regional disease:

• Doctors will often suggest hormone therapy in combination with radiation therapy.
• When your life expectancy is shorter based on other health problems, hormone therapy can be used by itself to slow the disease process.

If you have metastatic disease:

• Hormone therapy is typically the first treatment (referred to as first-line treatment) and is often used in combination with other medications.

If you have recurrent disease (cancer that has returned):

• Doctors will often recommend hormone therapy when the cancer has returned following initial treatment with radiation or surgery.

Doctors commonly recommend hormone therapy in various other instances as well. It is important to discuss all of the options, along with any questions and concerns you have, with your healthcare team. As a veteran, you may have access to hormone therapy and treatment support through the VA. You may also have opportunities for advanced treatments and trials not widely available elsewhere.

What types of hormone therapy are used in prostate cancer?

There are several drugs and mechanisms used for decreasing the availability of androgens (or male hormones) that cause prostate cancer cells to grow.

These can be broadly divided into three categories: Androgen deprivation therapy (ADT) which lowers the hormones made by the testicles, medication that lowers androgens produced in other parts of the body, and anti-androgens which block androgens from activating prostate cancer cells.

Androgen Deprivation Therapy (ADT)

The goal of ADT is to decrease production of androgens produced by the testicles. This can be done surgically or with medication.

Orchiectomy

Although not commonly performed, orchiectomy, is a surgery to remove both testicles. Because testicles produce the majority of androgens, removing them significantly decreases the level of male hormones. This treatment, although effective, is irreversible. Because of this, many men opt for medication instead.

LHRH agonist

Luteinizing hormone releasing hormone (LHRH) agonist refers to medication that decreases the levels of testosterone produced by the testicles. These medications lower male hormone levels similarly to an orchiectomy but leave the testicles intact.

These medications are often injected or implanted under the skin. They are typically given once a month, or once every several months.

Common medications in this category include:

• Leuprolide
• Goserelin
• Triptorelin

LHRH antagonist

LHRH antagonists, like LHRH agonists, reduce the production of male hormones by the testicles. However, they typically work faster than LHRH agonists.

Common medications in this category include:

• Degarelix (a monthly injection)
• Relugolix (a pill taken once daily)

Side effects of ADT

ADT, regardless of which medication or surgery used, significantly lowers male hormone levels.

The resulting effect of decreasing levels of hormones such as testosterone may include:

• Decreased sexual desire
• Fatigue
• Erectile dysfunction
• Hot flashes
• Weight gain
• Loss of muscle mass
• Depression
• Gynecomastia
• Anemia
• Decrease mental acuity
• Osteoporosis

It is important to talk to your doctor about the benefits and potential side effects from hormonal treatment. “We really talk a lot about living well with hormonal therapy, how to thrive and mitigate some of the side effects that we talk about,” Dr. Wise points out.

Abiraterone

While ADT can decrease the level of androgens produced by the testicles, additional areas of your body, such as the adrenal glands and prostate cells themselves, also produce androgens that stimulate the growth of prostate cancer cells. Additional medication can be considered in combination with ADT for treatment in very high-risk individuals with aggressive disease.

Once such drug is Abiraterone. This medication blocks the enzyme CYP17 which is involved in producing male hormones.

Abiraterone is usually used in conjunction with radiation and ADT in very high risk, localized prostate cancer and regional prostate cancer involving lymph nodes. Abiraterone can also be used with ADT among other medications in metastatic disease.

Anti-androgens

This medication class blocks androgens from attaching to androgen receptors, which are specific sites on prostate cancer cells. By preventing this attachment, the medications disrupt cell signaling which in turn stops the cancer cells from growing and spreading.

Common drugs in this category include:

• Enzalutamide
• Apalutamide
• Darolutamide

Medications in this class are often used in to treat metastatic prostate cancer in combination with ADT.

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