Prostate Cancer (cont.)
Kevin C. Zorn, MD, FRCSC, FACS
Gagan Gautam, MD, MCh
William C. Shiel Jr., MD, FACP, FACR
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
Dennis Lee, MD
Dennis Lee, MD
Dr. Lee was born in Shanghai, China, and received his college and medical training in the United States. He is fluent in English and three Chinese dialects. He graduated with chemistry departmental honors from Harvey Mudd College. He was appointed president of AOA society at UCLA School of Medicine. He underwent internal medicine residency and gastroenterology fellowship training at Cedars Sinai Medical Center.
In this Article
What about hormonal treatment for prostate cancer?
The primary male (androgenic) hormone is called testosterone. It stimulates the growth of cancerous prostatic cells and, therefore, is the primary fuel for the growth of prostate cancer. The idea of all of the hormonal treatments (medical and surgical), in short, is to decrease the stimulation by testosterone of the cancerous prostatic cells. Testosterone normally is produced by the testes in response to stimulation from a hormonal signal called LH-RH. The LH-RH stands for luteinizing hormone-releasing hormone and is also called gonadotropin-releasing hormone. This hormone comes from a control station in the brain and travels in the bloodstream to the testes. Once there, the LH-RH stimulates the testes to produce and release testosterone.
Hormonal treatment, also referred to as androgen deprivation (depriving the prostate of testosterone), can be accomplished surgically or medically. The surgical hormonal treatment is removal of the testes in an operation called an orchiectomy or a castration. This surgery thus removes the body's source of testosterone. The medical hormonal treatment involves taking one or two types of medication. One type is referred to as the LH-RH agonists. These drugs act like the leutinizing hormone-releasing hormone normally secreted by the hypothalamus in the brain, which in turn, stimulates the pituitary gland attached to the brain to release leutinizing hormone, which stimulates the testes to make testosterone. They work by competing with the body's own LH-RH. These drugs thereby inhibit (block) the release of LH-RH from the brain. The other type of drug is referred to as anti-androgenic, meaning that these drugs work against the male hormone. That is, they work by blocking the effect of testosterone and other male hormones made by the adrenal glands on the prostate cancer cells.
Today, most men electing hormonal treatment choose medication over surgery, probably because they view surgical castration as more devastating cosmetically or psychologically. Actually, however, the effectiveness and side effects of medical hormonal treatment as compared to surgical hormonal treatment are very much the same. Medication treatment is more expensive than is an orchiectomy. Both types of hormonal treatment usually effectively eliminate stimulation of the cancer cells by testosterone. Some tumors of the prostate, however, do not respond to this form of treatment. Some prostate cancers respond temporarily, but then progress in spite of the hormonal treatment being continued. They are referred to as androgen-independent prostate cancers. The principal side effects of all of these hormonal treatments (that is, the side effects of androgenic deprivation) are enlarged breasts (gynecomastia) that often are tender, flushing (like hot flashes), and impotence.
The LH-RH agonists, leuprolide (Lupron), goserelin (Zoladex), triptorelin (Trelstar), and histrelin (Vantas) are given as monthly injections in the doctor's office. Those offering Depot preparations may be given less often. The anti-androgenic drugs, flutamide (Eulexin), bicalutamide (Casodex) or nilutamide (Nilandron), are oral capsules that are used usually in combination with the LH-RH agonists. The LH-RH agonists are often effective alone. The anti-androgenic drugs are added, however, if the cancer progresses despite the use of the LH-RH agonists. The hormonal treatments may have value, as well, when combined with radiation therapy. Current evidence suggests that hormonal therapy enhances the therapeutic effect of radiation in cases of locally advanced prostate cancer. Today, newer treatments for prostate cancer which are hormonally based are emerging, including LH-RH antagonists (degarelix [Firmagon]), as well as another way to block androgen synthesis called abiraterone (Zytiga).
Generally, hormonal treatment is reserved for individuals who have advanced prostate cancer with local spread or metastases. Occasionally, an individual with organ-confined (localized) prostate cancer will receive hormonal treatment because he has severe associated medical problems or simply because he refuses to undergo surgery or radiation. Hormonal treatment is used less frequently in men with organ-confined (localized) prostate cancer. Remember that the intent of hormonal therapy usually is palliative. This means that the goal is to control the cancer rather than cure it because a cure is not possible.
Medically Reviewed by a Doctor on 12/9/2013