18 Sep Prostate:Hormone Therapy
Today’s topic will yet be another option for the treatment of prostate cancer. We all know that part of what makes men, men, is the fact that they have a large amount of testosterone in their bodies. Testosterone is a male hormone that is produced in the testicles. Many cells in the body respond to or are controlled by testosterone. Cells located inside of the prostate have receptors or “landing pads” that are attracted to testosterone. When these landing pads are exposed to testosterone, the testosterone lands and connects to the cell. When testosterone and the cell connect, it stimulates growth. (This picture is an illustration of what a receptor or a “landing pad” might look like.)
When cells that have “landing pads” for testosterone become cancerous, and then are connected or exposed to testosterone, the growth of these cancer cells will be increased and will grow more quickly.
The basis for hormone therapy is to block these receptors or “landing pads” from testosterone. If you block the testosterone, you will block the ability for the cell to grow and reproduce since there is no testosterone.
Hormone therapy is different from chemotherapy. In hormone therapy you are preventing cancer cells from growing by blocking the testosterone that promotes growth. This is also known as cytostatic. Chemotherapy is a process in which a medication inserted into the blood stream actually kills cancer cells. This is also known as cytotoxic therapy.
In men, there are two methods or ways of adminstering Hormonal Therapy. The first way is through medical hormone therapy. The second way is through a surgical procedure called an orchiectomy. I will discuss both of these therapies in the following paragraphs. Lets first begin with medical hormonal therapy.
Medical Hormonal Therapy
Any medicines that reduce male hormone levels are LHRH analogues and antiandrogens. Females hormones such as estrogen can also reduce male hormone levels, but can also cause some severe side effects, and are therefore rarely used.
LHRH Analogues: (luteinizing hormone releasing hormone or LHRH) These drugs turn off the signal for testosterone production by the testicles. By turning off the signal, hormone levels are reduced and cancer cells are not exposed to male hormones. In doing this, one prevents the growth of prostate cancer cells. LHRH analogues are given as a small injection under the skin of the abdomen every month or every three months. These drugs work just as effectively against prostate cancer as bilateral orchiectomy.
LHRH analogues can cause side effects such as loss of sexual desire, impotence, hot flashes and the development of osteoporosis, which increases the risk of bone fractures. Because these drugs require an injection every 1 or 3 months, LHRH analogues may not be as convenient as surgery. Unlike surgery, these drugs can be discontinued, and male hormone levels will return to normal.
Antiandrogens: Not all male hormones are made by the testicles. A small amount of male hormone is made by the adrenal glands, and may not be affected by bilateral orchiectomy or LHRH analogues. An antiandrogen is a medication that can block the effect of the remaining male hormone on prostate cancer cells. Antiandrogens are pills often given to patients in addition to orchiectomy or LHRH agonists. This combination of treatment is known as total or combined androgen blockade.
Antiandrogens can cause side effects such as loss of sexual desire, diarrhea, enlargement of the breasts and occasional impotence. When used alone, these drugs appear to cause impotence much less often than other forms of hormone therapy. On rare occasion, these drugs can cause liver abnormalities, and blood tests can help detect these problems before serious side effects occur. These drugs can also be discontinued, and male hormone levels gradually return to normal.
Several clinical studies have directly compared total androgen blockade with a single form of hormone therapy (LHRH analogue or orchiectomy) for patients with metastatic prostate cancer. Two large studies conducted in the U.S. and Europe have shown improvement in disease control and survival with total androgen blockade. In one study involving 603 patients, half the patients treated with a LHRH analogue were alive at 28 months and half the patients treated with combined androgen blockade were alive at 35 months. Most doctors feel combined androgen blockage controls disease and improves survival better than either an LHRH analogue or orchiectomy alone.
When to Start Hormonal Therapy?
There is general agreement that men experiencing symptoms from prostate cancer should begin treatment immediately. There has been some disagreement, however, regarding the best time to start hormonal therapy in asymptomatic patients. Researchers from London recently conducted a clinical trial comparing the timing of hormone therapy. Almost 1,000 men participated in the clinical study. Half received immediate hormonal therapy and half had hormonal therapy deferred until they developed symptoms. Patients treated with immediate hormonal therapy lived longer without cancer progression and were less likely to develop significant complications from cancer.
Bilateral orchiectomy (castration) is surgical operation to remove the testicles. By removing the testicles, the main source of male hormones is removed and hormone levels decrease. Orchiectomy is a common treatment for patients with metastatic (stage IV) prostate cancer who will likely require hormone therapy for life. Patients may experience a benefit in symptoms in a matter of days following surgery.
Orchiectomy can cause side effects such as loss of sexual desire, impotence, hot flashes, and weight gain. The operation itself is relatively safe and not associated with severe complications. Orchiectomy is a convenient and less costly method of hormone therapy; however, it is irreversible.
I hope this sheds some light on the topic of Hormonal Therapy and Prostate Cancer. If you have any other questions or concerns, please feel free to contact me directly at: CANCERGEEK@GMAIL.COM