Hormone Therapy

Prostate cancer cells are just like all other living organisms—they need fuel to grow and survive. Because the hormone testosterone serves as the main fuel for prostate cancer cell growth, it is a common target for therapeutic intervention in men with prostate cancer.

Hormone therapy, also known as androgen-deprivation therapy or ADT, is designed to stop testosterone from being released or to prevent the hormone from acting on the prostate cells. Although hormone therapy plays an important role in men with advancing prostate cancer, it is increasingly being used before, during, or after local treatment as well.

The majority of cells in prostate cancer tumors respond to the removal of testosterone. But some cells grow independent of testosterone, and therefore remain unaffected by hormone therapy. As these hormone-independent cells continue to grow unchecked, over time, hormone therapies have less and less of an effect on the growth of the tumor.

Hormone therapy is therefore not a perfect strategy in the fight against prostate cancer, and does not cure the disease. But it remains an important step in the process of managing advancing disease, and will likely be a part of every man’s therapeutic regimen at some point during his fight against recurrent or advanced prostate cancer.

The most common types of hormone therapy are described below. Although each of these therapeutic options is effective at controlling prostate cancer growth, the loss of testosterone confers significant side effects in nearly all men. (A review of how best to manage side effects from testosterone loss can be found in the Side Effects section.)

Orchiectomy
Because about 90% of testosterone is produced by the testicles, surgical removal of the testicles, or orchiectomy, is an effective solution to blocking testosterone release. This approach has been used successfully since the 1940s, but because it’s a permanent and irreversible surgical solution, most men opt for drug therapy instead.

For men who choose this option, the procedure is typically done on an outpatient basis in the urologist’s office. Recovery tends to be rather quick and no further hormone therapy is needed, making orchiectomy a very attractive choice for someone who prefers a low-cost, one-time procedure.

LHRH Agonists
LHRH, or luteinizing-hormone releasing hormone, is one of the key hormones released by the body before testosterone is produced. (Note that LHRH is sometimes called GnRH, or gonadotropin-releasing hormone.) Blocking the release of LHRH through the use of LHRH agonists or LHRH analogues is one of the most common hormone therapies used in men with prostate cancer.

Drugs in this class, including leuprolide (Eligard, Lupron, and Viadur), goserelin (Zoladex), and triptorelin (Trelstar), are given in the form of regular shots: once a month, once every three months, once every four months, or once per year.

Antiandrogens
LHRH agonists cause what is known as a "flare" reaction because of an initial transient rise in testosterone. This can result in a variety of symptoms ranging from bone pain to urinary frequency or difficulty.

Antiandrogens such as bicalutamide (Casodex), flutamide (Eulexin), and nilutamide (Nilandron), help to block the action of testosterone in prostate cancer cells. They are therefore often added to the LHRH agonist for at least the first 4 weeks of therapy when the flare reaction typically occurs. In this setting, antiandrogens can be helpful in preventing the flare reaction.

Although the sexual side effects of the antiandrogens when given alone are typically far fewer compared with the LHRH agonists, antiandrogens might not be as effective as orchiectomy or LHRH agonists and are not the optimal choice for men with documented metastatic prostate cancer.

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