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 tumor.
Hormone therapy may be used:
- Along with (or after) radiation treatment when there is a high risk of the cancer returning.
- When prostate cancer has come back.
- When prostate cancer is found outside the prostate in other parts of the body (metastatic) at the time of diagnosis.
When hormone therapy slows the growth of prostate cancer, a man's prostate-specific antigen (PSA) levels will go down. PSA tests will show if the treatment is working.
Medicines for hormone therapy
Taking medicine, such as luteinizing hormone-releasing hormone (LHRH) medicine, is one way to reduce androgens.
- LHRH agonists. These drugs stop the body from making testosterone. They include goserelin (Zoladex), histrelin (Vantas), leuprolide (Lupron), and triptorelin (Trelstar).
- LHRH antagonists. These drugs stop the body from making testosterone. They work right away. And they avoid the flare caused by LHRH agonists, which can make symptoms worse for several weeks. One LHRH antagonist is degarelix (Firmagon).
- Androgen inhibitors. These are medicines that block enzymes that the body needs to make testosterone. They include enzalutamide (Xtandi), ketoconazole, and abiraterone (Zytiga), which is given along with prednisone.
- Antiandrogens. These drugs often are used along with LHRH 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 nonsteroidal antiandrogens include bicalutamide (Casodex), flutamide, and nilutamide (Nilandron).
Other hormone therapies may include the use of medicines such as aminoglutethimide combined with hydrocortisone, corticosteroids (dexamethasone, hydrocortisone, and prednisone), estrogen, and megestrol.
Surgery as hormone therapy
Another way, used much less often, is surgery to remove the testicles, also known as an 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.
Timing of hormone therapy
Research does not clearly show whether starting hormone therapy before symptoms appear allows men to live longer than if they waited until after symptoms appear to start taking medicine.1 Men who start hormone therapy almost always stay on it for the rest of their lives. So waiting until symptoms appear may allow men to delay the serious 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. Antiandrogen monotherapy means taking antiandrogens without other hormone medicines.
- Combined androgen blockade (CAB). Sometimes androgen deprivation (orchiectomy or an LHRH agonist) and an antiandrogen are used together for treatment. This blocks the testosterone made by the testicles and the adrenal glands.
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.
- Emotional ups and downs.
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, cardiovascular disease, and a shorter life span.1
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. Low-dose radiation or taking tamoxifen may help prevent or reduce breast enlargement. For men with depression, counseling 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.