Hormone Therapy for Prostate Cancer (Androgen Deprivation Therapy, or ADT)

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Hormone Therapy for Prostate Cancer (Androgen Deprivation Therapy, or ADT)

Topic Overview

Hormone therapy for prostate cancer is also known as androgen deprivation therapy (ADT). Prostate cancer cannot grow or survive without androgens, which include testosterone and other male hormones. Hormone therapy decreases the amount of androgens in a man's body. Reducing androgens can slow the growth of the cancer and even shrink the tumour.

Hormone therapy may be used along with radiation treatment when there is a high risk of the cancer returning. Or hormone therapy may be used after surgery or radiation if any cancer remains.

Hormone therapy may also help men who have cancer that has spread and who cannot have surgery or radiation. It may be used when prostate cancer has spread outside the prostate (metastatic disease). In these cases, hormone therapy reduces pain and helps men live a little longer.1

Hormone therapy may be used to suppress prostate cancer cells, which is reflected in lower levels of prostate-specific antigen (PSA).

Hormone therapy may also be used as the main treatment for prostate cancer instead of surgery or radiation. But hormone therapy doesn't seem to help men ages 66 and older who have localized prostate cancer. These men live just as long with active surveillance.2

Taking medicines is one way to reduce androgens. Another way, used much less often, is surgery to remove the testicles, also known as an orchiectomy.

  • LH-RH agonists and GnRH agonists. These drugs stop the body from making testosterone. They include goserelin (Zoladex), leuprolide (Lupron), and triptorelin (Trelstar).
  • GnRH antagonists. These drugs stop the body from making testosterone. They work right away. And they avoid the flare caused by GnRH agonists, which can make symptoms worse for several weeks. One GnRH antagonist is degarelix (Firmagon).
  • Antiandrogens. These drugs often are used along with LH-RH agonists. Antiandrogens help block the body's supply of testosterone. There are steroidal antiandrogens and "pure" antiandrogens. The steroidal antiandrogens include megestrol (Megace). The "pure" or non-steroidal antiandrogens include bicalutamide (Casodex), cyproterone (Androcur), flutamide (Euflex), and nilutamide (Anandron).
  • Orchiectomy. This surgery is considered to be hormone therapy. This is because removing the testicles, where more than 90% of the body's androgens are made, decreases testosterone levels. Removing the testicles may be the simplest way to reduce androgen levels, but it is permanent.

Sometimes androgen deprivation (orchiectomy or an LH-RH agonist) and an antiandrogen are used together for treatment. This is called a combined androgen blockade (CAB). There is also a triple androgen blockade (TAB) where another medicine is added. But research doesn't yet show that TAB works better than other treatments.3

Other hormone therapies may include the use of medicines such as megestrol acetate, estrogen, ketoconazole, aminoglutethimide combined with hydrocortisone, and corticosteroids (prednisone, dexamethasone, and hydrocortisone).

Timing of hormone therapy

Some men choose to start hormone therapy only after they have symptoms. But many doctors recommend starting hormone therapy if cancer is found in the lymph nodes during surgery to remove the prostate. Early treatment may allow men to live a little longer. Other doctors say to wait, because waiting will delay the bothersome side effects of hormone therapy.

Alternatives to conventional hormone therapy

  • Intermittent androgen deprivation (IAD). This involves cycles of hormone therapy medicines. Taking breaks during hormone therapy gives men the chance to recover their ability to function sexually. It also gives relief from the other side effects of hormone therapy, including hot flashes and the effects on energy as well as bone and muscle mass. The long-term survival outcome of IAD compared to conventional ADT is not yet known.
  • Antiandrogen monotherapy. Antiandrogens are medicines that block the action of androgens in the body. When used alone, antiandrogens usually don't work as well as other hormone therapy. And they may increase the chance of death if taken by men who have localized cancer and who are using active surveillance.3
  • Oral sequential hormone therapy. In this treatment, medicines that block the action of androgens in the body are taken with medicines that stop other changes that happen with androgens. Most studies have used finasteride (Proscar) or dutasteride (Avodart). This therapy usually causes a steady, painful increase in the size of breast tissue. This side effect may be prevented by radiation to the breasts before starting this hormone therapy. Or surgery may be needed to remove the extra breast tissue. Early studies have shown good results. But it is not yet known whether oral sequential hormone therapy helps men who have prostate cancer live longer.

Side effects of hormone therapy

The side effects of hormone therapy increase with the length of time that a man uses this therapy. Some of the side effects from hormone therapy will go away when a man who is taking medicine finishes his hormone therapy. For a man who has an orchiectomy, the side effects of sterility and loss of sexual interest are immediate and permanent.

Side effects of hormone therapy may include:

  • Thin or brittle bones (osteoporosis).
  • Increased body mass (BMI) and higher levels of fats in the blood.
  • Reduced muscle mass.
  • Low red blood cell count (anemia) and fatigue.
  • Increased risk for diabetes and heart disease.

Other side effects may include hot flashes, erection problems and reduced sex drive, breast enlargement, and cognitive impairment. Some men may experience depression.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems).

Long-term side effects of hormone therapy

The long-term side effects of hormone therapy, even for men taking medicine, are not known. But hormone therapy has been linked to a higher risk for diabetes and cardiovascular disease.1

One large study found that hormone therapy appears to be linked to a higher risk of death from heart problems in men who had surgery for localized prostate cancer.4

Hormone therapy and quality of life

The side effects of hormone therapy for prostate cancer often affect a man's quality of life. But there are treatments that can help with some of the side effects listed above. For example, exercise can help counteract the loss of muscle mass and will help with fatigue. There are medicines that can help with hot flashes, nausea, diarrhea, and bone loss. Treatments are available for erection problems and a reduced sex drive. Radiation before hormone therapy may help prevent breast enlargement. For men with depression, counselling and medicine may help. For more information, see the topic Depression.

Above all, talk with your doctor about any of the symptoms you have while you are taking hormone therapy. Your doctor may know about a local support group for men who have prostate cancer.

References

Citations

  1. Saylor PJ, Smith MR (2010). Adverse effects of androgen deprivation therapy: Defining the problem and promoting health among men with prostate cancer. Journal of the National Comprehensive Cancer Network, 8(2): 211–223.
  2. Lu-Yao GL, et al. (2008). Survival following primary androgen deprivation therapy among men with localized prostate cancer. JAMA, 300(2): 173–181.
  3. National Comprehensive Cancer Network (2009). Prostate cancer. NCCN Clinical Practice Guidelines in Oncology, version 2.2009. Available online: http://www.nccn.org/professionals/physician_gls/f_guidelines.asp#site.
  4. Tsai HK, et al. (2007). Androgen deprivation therapy for localized prostate cancer and the risk of cardiovascular mortality. Journal of the National Cancer Institute, 99(20): 1516–1524.

Credits

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer J. Curtis Nickel, MD, FRCSC - Urology
Last Revised September 27, 2010

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