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Alternative hormone-blocker reduces
side effects in prostate cancer patients
BOSTON - June 28, 2004 - An alternative way of blocking androgen
activity in prostate cancer patients produces fewer side effects
and may be a better choice than standard hormone therapy for some
patients. In the July issue of the Journal of Clinical Oncology,
researchers from the Massachusetts General Hospital (MGH) describe
how patients taking bicalutamide, which inhibits androgen activity
by binding to the hormones' receptors, had improved bone density
and reported fewer unpleasant side effects than did those taking
leuprolide, a traditional form of hormone therapy that markedly
lowers androgen levels.
"The differences between the two groups were dramatic; bone
mineral density increased among men taking bicalutamide while men
in the leuprolide group lost bone," says Matthew Smith, MD,
PhD, of the MGH
Cancer Center, who led the study.
Since the male hormones called androgens can accelerate the development
of prostate cancer, reducing their activity is a standard part of
treating the disease. Most commonly this is done with drugs like
leuprolide, called gonadotropin releasing hormone (GnRH) agonists,
that stop the body's production of all sex hormones. However, totally
blocking hormone activity can lead to potentially serious side effects
such as loss of bone density, which increases the risk of fractures.
Earlier
studies by this MGH research team also showed that GnRH-agonist
treatment often leads to unwanted weight gain and increased body
fat.
Because bicalutamide blocks androgen activity in a way that does
not reduce hormone levels in the blood, the research team wanted
to see if using a single-drug treatment plan might avoid or reduce
side effects. Earlier research had shown that bicalutamide alone
is as effective as GnRH agonists for men with locally advanced prostate
cancer.
The investigators enrolled 51 men with nonmetastatic prostate cancer
who were randomly assigned to receive either bicalutamide or leuprolide
treatment for one year. Although the participants knew which treatment
they received, since the drugs are adminstered differently, those
who gathered and analyzed the study's data did not know which patients
were in which group.
At the end of the study period, blood levels of testosterone and
the female hormone estradiol had risen significantly in the bicalutamide
group but fallen in those receiving leuprolide. Bone mineral density,
which decreased in the leuprolide group, had increased in participants
receiving bicalutamide. While both groups had increases in body
fat and decreased lean body mass, those changes were more pronounced
in those receiving leuprolide. And unpleasant side effects - such
as hot flashes, fatigue and sexual effects - were reported less
frequently in men taking bicalutamide.
"Bicalutamide monotherapy may be an attractive alternative
to standard hormone therapy for some men with non-metastatic prostate
cancer," says Smith, who is an assistant professor of Medicine
at Harvard Medical School. While bicalutamide is approved as monotherapy
for prostate cancer in 55 countries, in the U.S. it is only approved
in combination with GnRH-analog therapy.
The study's co-authors are Melissa Goode, Anthony Zietman, MD, Francis
McGovern, MD, Hang Lee, PhD, and Joel Finkelstein, MD, all of the
MGH. The study was supported by grants from the National Institutes
of Health, the Doris Duke Charitable Foundation, and AstraZenaca,
which markets bicalutamide under the brand name Casodex.
Massachusetts General Hospital, established in 1811, is the original
and largest teaching hospital of Harvard Medical School. The MGH
conducts the largest hospital-based research program in the United
States, with an annual research budget of more than $400 million
and major research centers in AIDS, cardiovascular research, cancer,
cutaneous biology, medical imaging, neurodegenerative disorders,
transplantation biology and photomedicine. In 1994, MGH and Brigham
and Women's Hospital joined to form Partners HealthCare System,
an integrated health care delivery system comprising the two academic
medical centers, specialty and community hospitals, a network of
physician groups, and nonacute and home health services.
Media Contact: Sue
McGreevey, MGH Public Affairs
Physician Referral Service: 1-800-388-4644
Information about Clinical Trials
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