What is hormone therapy for prostate cancer?

Dr. Jan L. Shifren, MD
Fertility Specialist

Hormone therapy for prostate cancer is aimed at reducing testosterone levels. As a result, approximately 80 percent of men undergoing this therapy experience low desire, erectile problems and lack of orgasm.

Hormone therapy is also known as androgen deprivation therapy (ADT). Androgens are the male hormons such as testosterone and dihydrotestosterone. While there is no evidence that higher levels of androgens are associated with a greater incidence of prostate cancer, we do know that they can fuel a cancer's growth if present. So ADT is designed to slow cancer growth by either lowering levels of these hormones in the body or preventing androgens from affecting cancer cells. 

ADT is most appropriate for men with cancers that have metastasized to bone or other visceral sites. Some men with high-grade disease and rapidly rising PSADTs (or doubling time) are presumed to have metastasis even if they are not seen on imaging studies. In this setting, ADT is often initiated. It is not a cure, but it can shrink and slow the growth of prostate tumors even after the cancers have spread to distant sites in the body and control the disease for many years.

Hormone therapy is the primary treatment for prostate cancer when the disease has spread beyond the prostate gland to distant sites (metastatic disease). The goal of hormone therapy is to dramatically reduce testosterone levels in the blood and therefore, slow the rate of prostate cancer cell growth.

The potential effects of testosterone loss may include:

  • hot flashes
  • decreased sexual desire, erectile dysfunction
  • loss of bone density and increased fracture risk (osteoporosis)
  • fatigue
  • increased risk of diabetes and heart attacks
  • weight gain
  • decreased muscle mass
  • anemia

Many men who are on hormone therapy experience some of these effects, but the extent or degree is not possible to predict. Some of these effects are clinically manageable. A discussion (regarding pros/cons) should take place with your health care provider before beginning hormone therapy. Staying active or exercise is probably the best thing a man can do to prevent many of these side effects.

Both normal prostate tissue and prostate cancers depend on male sex hormones, called androgens, to grow. Testosterone is an androgen that is very important to the prostate gland. Men make androgens in their testicles. One of the ways to treat prostate cancer is through hormonal therapy, which removes androgens from the body. This causes the cancer to shrink and then grow more slowly.

There are a few different ways to remove or decrease androgens:

  • orchiectomy: surgical removal of the testicles
  • luteinizing hormone-releasing hormone (LHRH) agonists:drugs used to control the growth and spread of prostate cancer by largely shutting down the normal hormonal functions in men
  • anti-androgens: drugs that block androgen receptors
  • estrogens: hormones that reduce the level of testosterone

Different methods of deceasing androgens are often used in the same man having therapy. LHRH agonists with anti-androgens can totally block the production of androgen.

After a while, all prostate cancers will become resistant to hormonal therapy. However, this often takes many years. Hormonal therapy can add a lot of time in men with extensive prostate cancer or men who choose not to have surgery or radiation.

'There are a number of side effects associated with hormonal therapy for the treatment of prostate cancer, including impotence, breast enlargement, hot flashes, and muscle and bone loss.

Hormone therapy is often used for patients whose prostate cancer has spread beyond the prostate or has recurred after treatment. The goal of hormone therapy is to lower levels of the male hormones, also known as androgens. The main androgen is testosterone. Lowering androgen levels can cause prostate cancers to shrink or grow more slowly, but does not cure cancer. Methods of hormone therapy include:

  • orchiectomy—a surgical procedure to remove one or both of the testicles, which are the main source of male hormones; orchiectomy decreases hormone production, which can shrink or slow the growth of most prostate cancers;
  • luteinizing hormone-releasing hormone (LHRH) agonists—injections that can decrease the amount of testosterone produced by the testicles;
  • antiandrogens (e.g., flutamide, bicalutamide)—medications that can block the action of androgens; these medications are often used in combination with orchiectomy or LHRH agonists, a combination called total androgen blockade;
  • drugs that prevent adrenal glands from producing androgens (e.g., ketoconazole, aminoglutethimide);
  • estrogens—drugs that can prevent the production of testosterone in the testicles; estrogens are rarely used today because of the risk of serious side effects;

Possible side effects of hormone therapy include hot flashes, impaired sexual function, loss of sexual desire, and weakened bones.

Hormone therapy deprives cancer cells of the male hormones they need to grow. Prostate cancer hormone therapy is often used in combination with radiation and other therapies. Hormone therapy may be used to shrink advanced prostate cancer tumors, so they can be treated with radiation.

A common regimen for prostate cancer therapy uses a combination of two or more drugs to lower the level of testosterone and other hormones that can fuel the disease. In some cases, hormone therapy may be given intermittently to help reduce treatment-related side effects.

Supportive therapies are available to help manage potential side effects of prostate cancer hormone therapy, like mood changes and low libido. Side effects are anticipated by focusing on prevention, and managing them with a variety of approaches if they do occur. All of this is integrated into your overall treatment plan, with personalized support for you and your family.

By impeding testosterone, physicians can slow prostate cancer growth. While hormone therapy will not cure prostate cancer, it is often recommended in addition to another form of treatment or to keep the cancer from spreading too fast when no treatment is the recommended way to proceed.

Dr. Marc B. Garnick, MD
Hematologist & Oncologist

Hormone therapy is a prostate cancer treatment (with either drugs or surgery) intended to reduce or eliminate the supply of male hormones to the prostate and distant cancer sites, slowing cancer growth.

In the past, hormone therapy meant the surgical removal of both testicles, a procedure known as bilateral orchiectomy. Because more than 90 percent of androgens are produced in the testicles, orchiectomy immediately ceased production of most of the hormones fueling the growth of prostate cancer cells. But because many men find the idea of having their testicles removed psychologically difficult to accept and because the procedure can't be reversed, doctors now use drugs to dramatically lower androgen levels and slow prostate cancer. Doctors often recommend injectable drugs -- primarily luteinizing hormone-releasing hormone (LHRH) agonists. GnRH antagonists and anti-androgens, two other classes of drugs, are occasionally used. Other forms of hormonal therapy are now available for use in later stages of the disease. In the near future, many of these will become available for earlier stages of disease.

Evidence supports the combined use of hormone therapy and radiation for treating prostate cancer. A study in The Journal of the American Medical Association found that combining these two therapies was especially effective for patients with early-stage prostate cancer. In this study, 206 men with early-stage prostate cancer received either radiation alone or radiation plus six months of hormone therapy. After a median period of four-and-a-half years, the men who received radiation plus hormone therapy had significantly higher survival rates and significantly lower risk of relapse than men who received radiation only.

Because the drugs interfere with testosterone, sexual function is often a casualty of hormone therapy. Many men experience impotence and a loss of sexual desire. When treatment is stopped, however, sexual function usually returns. Hot flashes, nausea, and diarrhea are also common. Also, reduction in bone density and muscle mass occurs in some patients, and breast enlargement can be a significant problem. In addition, the anti-androgens have been linked with liver failure and should be used with caution. Patients who take them should have routine tests of liver function. A small number of men taking hormone therapy for prostate cancer develop joint pain or changes in memory or personality.

The goal of hormone therapy, which lowers levels of testosterone that causes prostate-cancer cells to grow, is sometimes to cure the cancer, such as when combined with radiation, but more often it is given to suppress the cancer and prolong survival when the cancer has advanced beyond the point where it can be cured. Common hormone therapies include:

  • Orchiectomy: Surgical removal of the testicles, which produce testosterone.
  • LHRH Analogs: Drugs that lower the amount of testosterone produced in a man’s body. Injections are given every one to four months (or even yearly).
  • Antiandrogens: These testosterone-blocking medicines are usually used in combination with orchiectomy or LHRH analogs.

When men's testosterone levels drop from hormone therapy, they lose muscle mass. They get muscle atrophy, which can lead to them getting weak and other problems. We're developing a program with two interventions for men on hormone therapy. One will be an exercise program, which will be led by a trainer. The other intervention will be a very intensive dietary program, because men on hormone therapy put on weight, which can be a problem.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.