Prostate Cancer

+ -Text Size

Treating Prostate Cancer TOPICS

Hormone (androgen deprivation) therapy for prostate cancer



Hormone therapy may be used:



Treatments to lower androgen levels

Orchiectomy (surgical castration)




Luteinizing hormone-releasing hormone (LHRH) analogs

These drugs lower the amount of testosterone made by the testicles. Treatment with these drugs is sometimes called chemical castration or medical castration because they lower androgen levels just as well as orchiectomy.

Even though LHRH analogs (also called LHRH agonists or GnRH agonists) cost more than orchiectomy and require more frequent doctor visits, most men choose this method. These drugs allow the testicles to remain in place, but the testicles will shrink over time, and they may even become too small to feel.



Degarelix (Firmagon®)



Abiraterone (Zytiga®)

Drugs such as LHRH agonists can stop the testicles from making androgens, but other cells in the body, including prostate cancer cells themselves, can still make small amounts, which can fuel cancer growth. Abiraterone blocks an enzyme called CYP17, which helps stop these cells from making androgens.


This drug is taken as pills every day. This drug doesn’t stop the testicles from making testosterone, so men who haven’t had an orchiectomy need to continue treatment with an LHRH agonist or antagonist. Because abiraterone also lowers the level of some other hormones in the body, prednisone (a cortisone-like drug) needs to be taken during treatment as well to avoid certain side effects.

Drugs that stop androgens from working


Androgens have to bind to a protein in the cell called an androgen receptor to work. Anti-androgens are drugs that bind to these receptors so the androgens can’t.

Drugs of this type, such as flutamide (Eulexin®), bicalutamide (Casodex®), and nilutamide (Nilandron®), are pills taken daily.

Anti-androgens are not often used by themselves in the United States. An anti-androgen may be added to treatment if orchiectomy, an LHRH analog, or LHRH antagonist is no longer working by itself. An anti-androgen is also sometimes given for a few weeks when an LHRH analog is first started to prevent a tumor flare.

Anti-androgen treatment can be combined with orchiectomy or an LHRH analog as first-line hormone therapy. This is called combined androgen blockade (CAB). There is still some debate as to whether CAB is more effective in this setting than using orchiectomy or an LHRH analog alone. If there is a benefit, it appears to be small.

Some doctors are testing the use of anti-androgens instead of orchiectomy or LHRH analogs. Some studies have found no difference in survival rates, but others have found anti-androgens to be slightly less effective.

In some men, if an anti-androgen is no longer working, simply stopping the anti-androgen can cause the cancer to stop growing for a short time. Doctors call this the anti-androgen withdrawal effect, although they are not sure why it happens.

Enzalutamide (Xtandi®)

This drug is a newer type of anti-androgen. When androgens bind to the androgen receptor, the receptor sends a signal to the cell’s control center, telling it to grow and divide. Enzalutamide blocks this signal.



Other androgen-suppressing drugs




Possible side effects of hormone therapy


  • Reduced or absent libido (sexual desire)
  • Impotence (erectile dysfunction)
  • Shrinkage of testicles and penis
  • Breast tenderness and growth of breast tissue
  • Anemia (low red blood cell counts)
  • Decreased mental sharpness
  • Loss of muscle mass
  • Weight gain
  • Fatigue
  • Increased cholesterol
  • Depression




Enzalutamide can cause diarrhea, fatigue, and worsening of hot flashes. This drug can also cause some neurologic side effects, including dizziness and, rarely, seizures. Men taking this drug are more likely to fall, which may lead to injuries.


  • Several drugs are available to help prevent and treat osteoporosis.
  • Depression can be treated with antidepressants and/or counseling.

There is growing concern that hormone therapy for prostate cancer may lead to problems thinking, concentrating, and/or with memory, but this has not been studied thoroughly. Studying the possible effects of hormone therapy on brain function is hard, because other factors can also affect how the brain works. Still, hormone therapy does seem to lead to memory problems in some men. These problems are rarely severe, and most often affect only some types of memory. More studies are being done to look at this issue.

Current issues in hormone therapy







At this time, it isn’t clear that this approach is better than continuous hormone therapy, and it may even be worse in some ways. In one study of men with advanced prostate cancer, it wasn’t clear that intermittent therapy helped men live as long as continuous therapy. While the men getting intermittent therapy did report fewer problems with impotence and sex drive 3 months into the study, there was no difference later on.



Castrate-resistant and hormone-refractory prostate cancer: These terms are both sometimes used to describe prostate cancers that are no longer responding to hormones, although there is a difference between the two.

Castrate-resistant means the cancer is still growing even when the testosterone levels are as low as what would be expected if the testicles were removed (called castrate levels). Levels this low could be from an orchiectomy, an LHRH agonist, or an LHRH antagonist. Some men might be uncomfortable with this term, but it is specifically meant to refer to these cancers, some of which might still be helped by other forms of hormone therapy, such as the drugs abiraterone and enzalutamide. Cancers that still respond to some type of hormone therapy are not completely hormone-refractory, so that term can’t be used.


Last Medical Review: 12/22/2014
Last Revised: 03/12/2015