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NEW (EXPERIMENTAL) TREATMENT
FOR PROSTATE CANCER
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By William J. Catalona, M.D.
Chief of Urology, Washington
University in St. Louis Intermittent Hormonal Therapy is a new, experimental
treatment option for prostate cancer.
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Previous Use of Hormonal Therapy
Hormonal therapy is usually effective in the
treatment of prostate cancer, especially for patients who have had recurrence of
their cancer after surgery or radiation therapy.
The principle of hormonal therapy is that the
male hormone, testosterone, stimulates prostate cancer cells to grow and spread.
If the testosterone concentration in the blood is reduced to low levels, most
prostate cancer cells will die or go into a dormant state for an indefinite
(though unpredictable) period of time.
In the past, hormonal therapy for prostate
cancer involved the continuous administration of female hormones by mouth or by
having the testicles removed.
Recently, new medications are available to
achieve the same results with fewer risks, and their effects are reversible when
they are discontinued.
The side effects of hormonal therapy can
include reduced sexual desire and sexual function, "warm waves" (similar to "hot
flashes" experienced by women during menopause), dry skin, and slowing of the
growth of facial hair.
With prolonged hormonal therapy, there can be
loss of muscle mass (unless a vigorous exercise program is followed), loss of
bone density (osteoporosis), anemia, and loss of energy. Some forms of hormonal
therapy can cause breast enlargement, gastrointestinal upset, blood clots, fluid
retention, shortness of breath, and increased risk for heart attack.
New Use of Intermittent Hormonal
Therapy
Recent studies have shown that hormonal therapy
may be given intermittently, thus providing the patient with a "vacation" from
its side effects.
A commonly used program for intermittent
hormonal therapy involves taking two different types of medication: (1) a pill
for 10 days and (2) two injections of another kind of medication three months
apart.
A testosterone "flare" response occurs during
the first 10 days after the injection (Lupron or Zoladex). That testosterone
"flare" in the first 10 days could cause the tumor to grow.
The 1-day course of an oral medication (such as
Casodex or Eulexin) along with the scheduled injection blocks the testosterone
"flare" response that occurs during the first 10 days after the injection. This
10-day course of oral medication to accompany injection is an essential
component of the intermittent hormonal therapy.
Illustration
The way this therapy works is as follows. A man
previously treated with radiation therapy develops a rising PSA level that
reaches 4 on December 31. The rising PSA is an indication that the cancer has
recurred.
On January 1, he would begin to take a 10-day
course of Casodex pills. On January 2, he would be given a Lupron injection that
would stay in his system for three months.
On April 1, he would check his PSA level (which
would probably be very low) and then receive his second 3-month Lupron
injection.
On July 1, he would check his PSA level again.
If it is still low, he would stop the hormonal therapy and monitor his blood PSA
level until it reaches a level of 4 again, which may take six months to a year
or more.
During this time, he would recover from the
side effects of hormonal therapy. When the PSA level is once again 4, he would
begin another 6-month cycle.
Although intermittent hormonal therapy is
experimental, preliminary clinical studies suggest that the results appear to be
equivalent to those of continuous hormonal therapy.
Courtesy of QUEST Newsletter, Urological
Research Foundation
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