Prostate Cancer - Hormone Therapy

Hormone Therapy

The majority of prostate cancers are hormone-sensitive, which means they depend on the male hormone (testosterone) as fuel for tumor growth. Of the 230,000 men diagnosed with prostate cancer in the United States, about one-third will require hormone therapy, which removes all traces of testosterone from the body in an effort to reduce the tumor size.

Hormone therapies work best on early-stage, high-grade tumors (Gleason score of 8 or higher). However, there is disagreement over the length and timing of hormone therapy. Most studies have shown that suppression of testosterone at an earlier stage has a significant effect on patient survival. There are differing opinions on length of therapy, but M. D. Anderson oncologists agree that therapy spanning three years produces the best results.

There are three types of hormone therapies for prostate cancer:

Androgen ablationblocks the ability of cancer cells to interact with testosterone at the cellular level. Flutamide and Casodex are two types of androgen ablation drugs. They are taken orally on a daily basis for up to three years. Their effects are permanent in most patients.

The standard of care for early-stage, high-grade disease is androgen ablation given at least two months before radiation therapy. The drugs make the tumor more responsive to radiation treatment, and reduce the number of cancer cells to be treated.

LHRH agonistswork by overstimulating the pituitary gland to release luteinizing hormone-releasing hormone (LHRH), which signals the testicles to suppress testosterone production. Zoladex and Leuprolide are LHRH agonist drugs, administered by regular injections ranging from once a month to once a year. A disadvantage of this therapy is that it causes a short spike in testosterone levels before suppression takes effect. However, its effects are not permanent, so patients who cannot cope with treatment side effects can be taken off the drug and can resume testosterone production.

Orchiectomy(surgical removal of the testicles) used to be the standard hormone therapy for prostate cancer. Because orchiectomy is an efficient, cost-effective and convenient method of reducing testosterone, it is still an option for certain patients, particularly elderly men.

Side Effects of Hormone Therapies

• Impotency, loss of sex drive
• Loss of muscle mass, weakness
• Decreased bone mass (osteoporosis)
• Shrunken testicles
• Depression
• Loss of self-esteem, aggressiveness/alertness and higher cognitive functions such as prioritizing or rationalization

The severity of side effects increases with the length of hormone therapy. M. D. Anderson researchers are exploring other alternatives to minimize side effects, including earlier administration of hormone therapy before the disease has advanced, or using it intermittently to achieve similar results to continuous therapy.

Advanced Disease
For men with advanced or metastatic prostate cancer, hormone therapies provide relief from pain and other cancer-related symptoms. In these patients, the symptoms of advancing cancer outweigh the side effects of hormone therapy.