Prostate cancer is one of the most commonly diagnosed cancers in the United States, affecting an estimated 1 in 8 men during their lifetime.

Although prostate cancer is a serious disease, it’s also very treatable. Proactive screening and improved treatment options have made prostate cancer a highly survivable disease, with almost 97 percent of people surviving for at least 5 years after diagnosis.

Hormone therapy is a mainstay of prostate cancer treatment that works to prevent cancer cells from growing.

A combination of surgical and medical hormone therapies may be used to treat prostate cancer, including a class of medications known as anti-androgen drugs, or androgen receptor inhibitors.

In this article, we take a closer look at how anti-androgens work to treat prostate cancer and when they may be used in prostate cancer treatment.

Language matters

Sex and gender exist on spectrums. This article uses the terms “men” and “males” to refer to sex assigned at birth. Your gender identity may not align with how your body responds to this disease.

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Androgens are a group of sex hormones that play a role in body development. Testosterone is one of the most well-known androgens.

In males, androgens play a role in a variety of processes, including:

  • bone and muscle development
  • regulation of puberty
  • development of primary and secondary sex characteristics

Androgens are also involved in prostate growth and function. The prostate is a reproductive organ that is partially responsible for the production of semen.

When the functioning of androgen hormones is dysregulated, it can cause the abnormal growth of cells in the prostate, leading to prostate cancer.

Anti-androgens are a class of medications that work to inhibit the activity of androgens causing tumor growth.

This is done by binding to androgen receptors within prostate cancer cells, which blocks the binding of androgen molecules.

By blocking androgens from binding to receptors, anti-androgens prevent communication that would normally promote cell growth and survival.

Early in the course of the disease, prostate cancer cells rely on androgen signaling. Anti-androgen therapy effectively starves the cells of these signals, making it more difficult for them to grow.

Anti-androgen drugs block dihydrotestosterone (DHT) from binding with prostate cancer cells. This prevents luteinizing hormone secretion and leads to a decrease in testosterone production.

Anti-androgens are taken as a daily oral medication and may be used alone or in combination with other surgical or medical treatments.

There are two main types of anti-androgens that are currently used to treat prostate cancer:

  • first-generation anti-androgens
  • second-generation anti-androgens

First-generation anti-androgens that are commonly used to treat prostate cancer include flutamide, bicalutamide, and nilutamide. These first established anti-androgen drugs as an effective therapy for slowing cancer cell growth.

Second-generation anti-androgens are newer versions of anti-androgens that bind the androgen receptor more tightly to more effectively block androgen receptor-mediated signaling.

The most commonly used second-generation anti-androgens are enzalutamide and apalutamide.

Anti-androgens are typically reserved for advanced stages of prostate cancer, such as when cancer has spread to other parts of the body.

Anti-androgens are sometimes prescribed in addition to orchiectomy (surgical removal of the testicles) or luteinizing hormone-releasing hormone (LHRH) agonists when these therapies aren’t working alone. They may also be prescribed with these treatments as first-line therapy.

Prostate cancer that doesn’t respond to other types of androgen deprivation therapy is known as castration-resistant prostate cancer.

The American Urology Association also stated in 2018 that second-generation anti-androgens can be used earlier in prostate cancer along with other pharmaceutical hormone therapies for people who are likely to have their cancer spread to other parts of the body.

In some cases, prostate cancer cells can become resistant to first-generation anti-androgens. They may develop mutations that prevent binding to the androgen receptor or that allow the receptor to become activated after binding to the anti-androgen itself.

If this happens, you may still respond to second-generation anti-androgens, and your oncologist may recommend a change of treatment.

Anti-androgens are associated with a variety of possible side effects, including:

  • diarrhea
  • breast tenderness or tissue growth (known as gynecomastia)
  • hot flashes
  • reduced sex drive
  • erectile dysfunction

In rare cases, particularly with the use of flutamide, liver injury can occur. Talk with your doctor about monitoring your liver values during treatment.

Nilutamide can also cause problems with visual adaptation to light and, in rare cases, inflammation and scarring in the lungs. If you develop a persistent cough or shortness of breath, you should discuss your symptoms with your oncologist immediately.

Second-generation anti-androgens may have additional possible side effects including:

  • increased risk of bone fractures
  • seizures
  • dizziness and falls

Additional medication may be prescribed by your oncologist to help manage the side effects of anti-androgens, such as bisphosphonates for bone growth.

Exercise can also help with many side effects of prostate cancer and prostate cancer treatment, including muscle loss and fatigue.

Anti-androgens are a cornerstone of hormonal therapy for prostate cancer, particularly in the later stages of the disease.

These medications work by keeping androgens from binding to receptors, which in turn blocks cancer cell growth and survival.

While anti-androgens are a highly effective treatment option for advanced prostate cancer, they can be associated with some unpleasant side effects.

Before starting anti-androgen therapy, it’s important to talk with a healthcare professional to make sure you are fully prepared for the benefits and drawbacks of anti-androgen therapy.