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 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 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.footnote 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.
Effectiveness of hormone therapy
Hormone therapy usually works well at first to stop cancer growth. But in most cases, the cancer begins to grow again within a few years. At this point, the cancer is described as hormone-resistant, meaning it is not responding to standard hormone therapy. When this happens, other kinds of hormone treatments may be tried.
When hormone treatments no longer keep the cancer from growing, the cancer is called castrate-resistant prostate cancer (CRPC). Treatments that may be used to help men live longer include chemotherapy, immunotherapy, and medicines like enzalutamide.
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
Medicine
In men who take medicine for hormone therapy, the side effects get worse over time. Some of the side effects will go away after the man stops taking the medicine. Side effects 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.
Other side effects may include hot flashes, erection problems and reduced sex drive, breast enlargement, and cognitive impairment. Some men may experience depression.
Surgery
In men who have surgery for hormone therapy, two side effects happen right away and are permanent-the man becomes sterile and loses interest in sex. Other than those two side effects, surgery tends to have fewer side effects than medicine.
See Drug Reference for a full list of side effects. (Drug
Reference is not available in all systems).
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.