The majority of prostate cancers are hormone-sensitive, which means male hormones (androgens) such as testosterone fuel growth of the cancer.
About one-third of prostate cancer patients require hormone therapy (also called androgen deprivation), which blocks testosterone production or blocks testosterone from interacting with the tumor cells. This reduces the tumor size or makes it grow more slowly. While hormone therapy may help control prostate cancer, it does not cure it.
Hormone therapy is most often used for late-stage, high-grade tumors (Gleason score of 8 or higher) or in patients with cancer that has spread outside the prostate. However, doctors have different opinions about the length and timing of hormone therapy.
Hormone therapy may be used to treat prostate cancer if:
- Surgery or radiation is not possible
- Cancer has metastasized (spread) or recurred (come back after treatment)
- Cancer is at high risk of returning after radiation
- Shrinking the cancer before surgery or radiation increases the chance for successful treatment
Intermittent hormone therapy is a variation of hormone therapy in which drugs are used for a period of time, then stopped and started again. For some men, this approach to prostate cancer causes fewer side effects. The effectiveness of this approach is still being studied, but it appears particularly useful in some situations.
The types of hormone therapies for prostate cancer are:
- Anti-androgens: These drugs, which include Eulexin® (flutamide or flutamin) and Casodex® (bicalutamide), block testosterone from interacting with the cancer cell. They are taken by mouth every day.
Anti-androgens are used most often in combination with LHRH agonists (see below). Occasionally, anti-androgens are used as an alternative to LHRH agonists if the side effects are excessive for the patient.
- LHRH agonists: These drugs work by over-stimulating the pituitary gland to release luteinizing hormone-releasing hormone (LHRH). After an initial surge, this signals the testicles to suppress testosterone production. Treatments are injections, which last from one to six months, or implants of small pellets just under the skin.
LHRH agonists may cause a spike or flare in the testosterone level before treatment takes effect. To offset this effect, anti-androgens may be given for a few weeks before the initial LHRH injection. The effects of LHRH are usually not permanent, such that testosterone production may resume once the medication is stopped.
- Orchiectomy: Surgical removal of the testicles. This removes the organ, which produces testosterone, and is another way to keep testosterone from the prostate cancer. Orchiectomy is an efficient, cost-effective and convenient method of reducing testosterone, and it is an option if you will be treated with testosterone suppression indefinitely. After this surgery, most men cannot have erections.
Side effects of hormone therapies for prostate cancer may include:
- Impotence, inability to get or maintain an erection
- Loss of libido (sex drive)
- Hot flashes
- Growth of breast tissue and tenderness of breasts
- Loss of muscle mass, weakness
- Decreased bone mass (osteoporosis)
- Shrunken testicles
- Loss of self-esteem, aggressiveness/alertness and higher cognitive functions such as prioritizing or rationalization
- Anemia (low red blood cell count)
- Weight gain
- Higher cholesterol levels
- Increased risk of heart attacks, diabetes and high blood pressure (hypertension)
If you are treated with hormone therapy and have side effects, be sure to mention them to your doctors. Many of these side effects can be treated successfully.