Drug safely cuts prostate cancer risk, study finds
(AP) Long-term results from a major
federal study ease worries about the safety
of a hormone-blocking drug that can lower a
man's chances of developing prostate
cancer.
The drug cut prostate cancer risk by 30
percent without raising the risk of dying of an
aggressive form of the disease as earlier
results hinted it might.
The new work could prompt a fresh look at
using the drug for cancer prevention. Experts
say it could prevent tens of thousands of
cases each year, saving many men from
treatments with seriously unpleasant side
effects.
The drug is sold as Proscar by Merck & Co.
and in generic form as finasteride to treat
urinary problems from enlarged prostates.
It's also sold in a lower dose as Propecia to
treat hair loss.
A decade ago, the drug was found to cut the
risk of prostate cancer. But there was a
small rise in aggressive tumors among its
users. Some researchers said that by
shrinking the prostate, the drug was just
making these tumors easier to find in a
biopsy sample not causing them.
But the concern led the Food and Drug
Administration to turn down the drug for
cancer prevention and warnings were added
to its label.
Now, with 18 years of follow-up from that
earlier study, researchers report that men on
the drug were no more likely to die than
those not taking it.
That's reassuring because if the drug were
truly spurring lethal tumors, there would have
been more deaths among its users as time
went on, said Dr. Michael LeFevre, a family
physician at the University of Missouri.
LeFevre wrote an editorial that appears with
the study in Thursday's New England Journal
of Medicine. He is one of the leaders of the
U.S. Preventive Services Task Force, an
independent panel of doctors who advise the
federal government. The group has not taken
a stance on finasteride for prevention but
has advised against screening with PSA blood
tests.
Screening does more harm than good, the
panel has said, because although 240,000
new prostate cancers are diagnosed each
year in the United States, only about 30,000
prove fatal. That means many men are
treated for cancers that grow too slowly to
be life-threatening, and often suffer sexual
and urinary problems as a result.
The study, led by Dr. Ian Thompson at the
Cancer Therapy and Research Center in San
Antonio, was done to see whether finasteride
could lower the risk of prostate cancer in
men who were getting screened with annual
PSA blood tests, as many still choose to do.
Researchers assigned 18,882 men 55 or older
with no sign of prostate cancer on blood
tests or a physical exam to take finasteride
or dummy pills for seven years. When the
study ended, those who had not been
diagnosed with prostate cancer were offered
biopsies to check for hidden signs of the
disease.
For the new analysis, researchers tracked the
study participants for a longer time 18 years
in all since enrollment began. Only about 10
percent of men on finasteride developed
prostate cancer versus 15 percent of those
on dummy pills. Aggressive tumors were
found in 3.5 percent of men on the drug
versus 3 percent of the others. Yet 78
percent of both groups were alive after 15
years.
That means the drug cannot be recommended
to prolong life, just to ease suffering by
preventing disease, LeFevre said.
"You may be preventing cancers that don't
need to be prevented" because so few are
life-threatening, but screening is finding
these tumors anyway and leading to
unnecessary treatments, he said. Reducing
that number is a valid reason to use a
prevention drug, he said.
Finasteride's other impact is financial.
Proscar and a similar drug, GlaxoSmithKline
PLC's Avodart, cost about $4 a pill. Generic
finasteride is available for less. Insurers
cover it when prescribed to treat urinary
problems but may not pay if it's used solely
for cancer prevention.
The drug also can cause hot flashes, fatigue,
weakness, low sex drive and trouble having
sex.
"A man certainly needs to know what he's
getting into if he decides to take this,"
LeFevre said.
