FRIDAY, Oct. 7 (HealthDay News) -- News that a key government
advisory panel will give a thumbs-down next week to a controversial
blood test for prostate cancer is garnering both praise and
condemnation from experts.
A draft report due out early next week from the United States
Preventive Services Task Force (USPSTF) will recommend that healthy
men forego regular prostate-specific antigen (PSA) testing aimed at
spotting prostate cancer, the
The New York Times and other media outlets reported
The USPSTF is the same independent group of medical experts that
caused a firestorm in late 2009 when they ruled against the use of
annual mammographies for average-risk women in their 40s.
The PSA test has been similarly controversial, since its overall
benefit in saving mens' lives has been challenged by a number of
studies. Among the reasons the USPSTF cited in rejecting the PSA
test is that the screen does not save lives and instead can result
in unnecessary treatments that can leave men with discomfort,
impotence and incontinence.
According to the
Times, the task force focused on the results of five trials, the two largest done in Europe and in the United States. The European trial included 182,000 men. Over nine years of follow-up, it found no reduction in deaths due to prostate cancer among men of all ages in the study who were underwent PSA testing. But it did find some reduction in deaths among men aged 55 to 69 who got the blood test.
The American trial, involving almost 77,000 men followed for
over a decade, also failed to show an overall reduction in deaths
among all the men who were screened.
"Unfortunately, the evidence now shows that this test does not save men's lives," Dr. Virginia Moyer, a professor of pediatrics at Baylor College of Medicine and chairwoman of the task force, told the Times. "This test cannot tell the difference between cancers that will and will not affect a man during his natural lifetime. We need to find one that does."
But Dr. Anthony D'Amico, chief of radiation oncology at Brigham
and Women's Hospital in Boston and a prostate cancer expert, said
the task force's recommendation is misguided.
D'Amico noted that in the European study, screening reduced
cancer deaths among these younger men by 44 percent. The U.S. study
also showed a 44 percent reduction in cancer death among younger
men, he added. "If they look at all the screening studies, they
will find that the people who benefited most from screening were
the youngest and presumably the healthiest," he noted.
"The panel has not really appreciated the entirety of the evidence," D'Amico said. "Considering all of the data, it appears that younger or healthier men benefit from PSA screening."
Right now, most men are advised to undergo regular PSA tests
beginning at age 50. However, because most prostate cancers grow
very slowly and may never prove fatal, the value of early treatment
has come into question.
Of course, some prostate tumors are aggressive and can prove
deadly. Most experts acknowledge that the real problem, right now,
is that there's no reliable test to tell a patient which type of
tumor he might have.
Dr. Otis W. Brawley, chief medical officer of the American
Cancer Society, also cautioned that the task force's decision is
not yet set in stone.
"It is important to keep in mind that under the new USPSTF process, the recommendation is not final until the conclusion of the public comment period and the USPSTFs review of those comments," he said.
According to Brawley, the cancer society pored over the existing
body of evidence in 2009 and at that point it determined that it
could not conclude whether or not PSA screening saves lives.
"We have long been concerned, and it has been very apparent for some years, that some supporters of prostate cancer screening have overstated, exaggerated and, in some cases, misled men about the evidence supporting its effectiveness," Brawley said. "We need balanced, truthful information to be made widely available to physicians and patients when making important health decisions. Sadly, that has not happened with this disease."
Brawley believes men must have an opportunity to make an
informed decision with their health care provider about screening
for prostate cancer after they receive information about the
uncertainties, risks and potential benefits associated with testing
for early prostate cancer detection.
"The ACS also strongly asserted that prostate cancer screening should not occur without an informed decision-making process," Brawley added.
D'Amico, who supports PSA testing, added that while
over-treatment based on PSA test results has been a problem, much
of that can be eliminated if the test is based on the most accurate
PSA results. To make the test more accurate, men should stay away
from sexual activity just prior to the test, bike riding, horseback
riding and colonoscopy, he said. In addition, they should not have
a PSA test if they have a bladder or prostate infection; and should
wait at least a month after it has cleared up.
"Also, once a person is diagnosed it doesn't mean that they have to undergo treatment -- they can have a discussion with their physician about the significance of this cancer," D'Amico said. "Diagnosing allows one to have the opportunity to understand whether this is a cancer that requires treatment or not. But, putting your hands over your eyes saying, 'I don't want to know,' actually can lead to unnecessary death."
"I would still recommend an annual PSA, particularly for men who are healthy and under 65," D'Amico concluded.
Another expert, Dr. Lionel L. Banez, also supports continued use
of the test. Banez, an assistant professor in the division of
urologic surgery at Duke University Medical Center, said "the draft
of the USPSTF review does provide evidence that PSA screening
reduces prostate cancer mortality -- albeit not in as great a
magnitude to be called optimal."
Prostate cancer remains the second most common cause of cancer
death in men after lung cancer, Banez noted. "Thus, a slight
reduction in mortality could still translate in a substantial
absolute number of lives saved. Though it is clear that we still
need to find a better test to improve early detection of
significant disease and to curtail over-treatment, it is not
advisable to discourage use of a currently existing test that is
proven to save lives," he said.
For more on prostate cancer, visit the
U.S. National Cancer Institute.
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