Hormone therapy for prostate cancer – How does it work?

The main purpose of hormone therapy for prostate cancer is to either:

  • Lower the amount of hormones that are produced in a man’s body
  • Stop the cancer cells from using these hormones

That’s why it is sometimes referred to as “androgen deprivation therapy” or “androgen suppression” therapy.

The hormone problem

Certain male hormones — such as androgens that are primarily produced in a man’s testicles — can cause prostate cancer cells to grow.

Testosterone is a type of androgen that affects the growth of prostate cancer cells.

Effective but not curative

While hormone therapy for prostate cancer may help slow down the growth of prostate cancer cells, or may shrink the cancer, it is not considered to be a cure.

It can be quite effective when used before radiation, and is sometimes used before surgery.  It may also be used in combination with radiation.

It is a treatment that can target prostate cancer throughout the body.  That is why it is often used when:

  • Surgery or radiation fail
  • Cancer has spread outside the prostate gland and cannot be cured by surgery or radiation alone

May stop working over time

Unfortunately, prostate cancer often becomes resistant to long-term hormonal therapy.  The term hormone-refractory is used when cancer stops responding to any type of hormone therapy.

To combat this, treatment may be stopped for periods of time and then restarted again. There is not clear agreement among physicians about when is the best time to start and stop hormone therapy for prostate cancer.

You may also hear the term castrate resistant.  This means that cancer is still growing, even when therapy is keeping testosterone levels at castrate levels, which are very low.

The effectiveness of hormone therapy for prostate cancer is usually monitored by PSA testing.

Types of hormone treatment for prostate cancer

Luteinizing hormone-releasing hormone analogs/agonists:

  • Cause a drop in the amount of testosterone produced in the testicles
  • Usually injected with a needle or implanted under the skin
  • Generally taken every month or at different intervals (ranges from every 3 months to every year)
  • Often called chemical castration

Luteinizing hormone-releasing antagonists

  • Injected drug that also works to stop the production of testosterone in the testicles
  • Works quickly
  • Does not cause a rise in testosterone levels (called tumor flares) like luteinizing hormone-releasing hormone agonists can


  • Oral drugs (pills) that block a man’s body from being able to use androgens (such as testosterone)
  • May be used in combination with other therapies
  • May have fewer sexual side effects when used alone



  • Sometimes used, particularly if androgen deprivation therapy stops working
  • Stop testosterone from being produced in a man’s body
  • Can cause breast enlargement and other potential health risks, such as blood clots


Some physicians treat men with a combined androgen blockage (antiandrogens in combination with androgen deprivation therapy such as luteinizing hormone-releasing hormone agonists or antagonists) than with antiandrogens alone.

Others suggest using a triple androgen blockage (antiandrogens, plus a luteinizing hormone-releasing hormone agonist or antagonist, and a 5-alpha reductase inhibitor).

More clinical studies are needed to determine what combinations of hormone therapy for prostate cancer can be most effective.

Potential side effects

One side effect that can be very frustrating for both men and their loved ones following hormone therapy for prostate cancer is that men may have little or no desire for sex.

It may help to keep reminding yourself that your partner’s lack of desire has nothing to do with his feelings for you.  It’s just an unwanted side effect of these drugs.


Other side effects of hormone therapy for prostate cancer can include:

  • Impotence
  • Hot flashes
  • Sore or swollen breasts
  • Weight gain
  • Tiredness
  • Constipation
  • Dizziness
  • Depression

Diarrhea, nausea, and liver problems have been associated with antiandrogens.

In addition to hot flashes, enzyme inhibitors (such as abiraterone), can cause:

  • Joint or muscle pain
  • High blood pressure
  • Fluid build-up
  • Upset stomach
  • Diarrhea

Other medical problems that can develop include:

  • Osteoporosis
  • Anemia
  • Decreased muscle mass

Some studies have shown that the risk of cardiovascular problems may rise, including:

  • High blood pressure
  • High cholesterol
  • Heart attacks
  • Risk of getting diabetes

Thinking, concentration, and memory problems are other side effects that have not been well studied, but can be disconcerting. Age may also be a factor.

Tumor flares

When men first use luteinizing hormone-releasing hormone analogs/agonists, they may experience a tumor flare.

This may cause bone pain in men who have cancer that has spread to the bone, or spinal chord compression if the cancer has spread to the spine.

Help for side effects

  • Hot flashes can often be helped by taking antidepressants
  • There are drugs to help prevent and treat osteoporosis
  • Brief radiation treatment to the breasts may help prevent enlargement
  • Exercise has also been shown to help fight fatigue, weight gain, and loss of bone and muscle mass


Return to treatments


The American Cancer Society. Prostate Cancer. http://www.cancer.org. Accessed March 17, 2015.

US TOO International, Inc. Pathways for new prostate cancer patients. http://www.ustoo.com. Accessed September 1, 2008.

Bostwick DG, Crawford DE, Higano CS, Roach M, eds. American Cancer Society’s Complete Guide to Prostate Cancer. Atlanta, GA: American Cancer Society Health Promotions; 2005.

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