WEDNESDAY, Oct. 20 (HealthDay News) -- The U.S. Food and Drug
Administration on Wednesday called for new warnings on the labels
of widely used hormonal prostate cancer drugs because of evidence
of a slight increased risk of heart disease and diabetes in the men
who take them.
The FDA first announced in May that it was reviewing the
prostate cancer drugs known as gonadotropin-releasing hormone
(GnRH) agonists, citing this possible increased risk. These
medications suppress the production of testosterone, a hormone that
can spur the growth of prostate cancer. The drugs include Eligard,
Lupron, Synarel, Trelstar, Vantas, Viadur, Zoladex and several
Hormone-based therapy is not a cure for prostate cancer, because
tumors can eventually become resistant to the therapy. However, the
therapy can extend survival.
So, should the new label warnings deter men from enrolling on
hormone-based treatment? Experts say the cardiovascular risk is
something to consider, but the therapy does have real benefits.
"Clearly these drugs are needed for the treatment of prostate cancer," Dr. Mark Soloway, chair of urology at the University of Miami Miller School of Medicine, stressed in May.
"Lowering the male hormone is by far the most effective treatment," he said, but at the same time "there should be more judgment in prescribing GnRH agonists."
Soloway believes that any increased risk for heart disease and
diabetes would be due to a lowering of testosterone. "At this
point, it makes sense to use hormone therapy when necessary, but
not for everyone that has prostate cancer," he said.
Another expert, Dr. Nelson Neal Stone, a clinical professor of
urology and radiation oncology at Mount Sinai School of Medicine in
New York City, agreed that, "there is evidence that low
testosterone can induce metabolic syndrome," which in turn raises
men's risk for diabetes and heart attack.
Speaking after the FDA's announcement earlier this spring, Stone
said studies have shown that men with advanced prostate cancer who
take hormone therapy face a twofold increased risk of developing
metabolic syndrome, a cluster of symptoms tied to the development
of heart disease.
"When I speak to patients who have to go on these agents, I counsel them about the risks of increased weight gain and I tell them they need to monitor their carbohydrate intake and increase their amount of exercise, and they can decrease the risk of developing metabolic syndrome," he said.
Patients with prostate cancer typically do have some treatment
choices. After initial treatment for prostate cancer, whether by
surgery or radiation, doctors usually track blood levels of
disease-linked prostate-specific antigen (PSA) over time. Based on
that, one can initiate hormone therapy, Soloway said, or simply
wait and monitor the patient.
"There is further evidence that you should not begin hormone treatment until such time when there is more compelling reason than just a slight rise in PSA," Soloway said. "There are hundreds and hundreds of thousands of such patients."
Soloway believes that many men across the United States are
unnecessarily taking hormone therapy for prostate tumors that have
not yet spread. "I think hormone therapy can be delayed for months
to years in some of these men," he said.
For men with more advanced metastatic prostate cancer, hormone
therapy can be used for several months until the PSA goes down, at
which point the therapy can be stopped, Soloway said. "If you stop
it for the time it takes for the PSA to rise again, that could be
many months to a couple or more years," he said.
Men taking hormone therapy need to understand that, as with any
drug treatment, there are some risks, Soloway said. But heart
disease is largely preventable, and he believes that GnRH agonists
might boost heart risks because they cause men to pile on extra
So, "you want to do what you can to decrease your chance of
diabetes, cardiovascular disease. This has to do with diet, keeping
your weight down," Soloway said.
For Stone, the toughest part is striking a balance between
cancer risk and risks from the number one killer of men, heart
disease. "It doesn't make much sense to try and treat their
prostate cancer and prevent them from dying from prostate cancer if
we are going to increase their risk of then dying from heart
disease," he reasoned.
Once patients understand that, Stone hopes they will be
motivated to watch their diet and exercise.
In the meantime, men should not stop taking their hormone
therapy, but do everything they can to reduce their risk of
developing cardiovascular disease and diabetes with lifestyle
changes, he said.
"There is always a price you pay for medications," Stone said. "But if we're aware of the consequences of taking the medication, then we can deal with that."
For more information on prostate cancer, visit the
American Cancer Society.