Granted, while both studies had their particular limitations, the PSA
test has its own limitations. For example, an elevated PSA can be a
tip-off to a lethal cancer, but it can also detect less aggressive
cancer that may never cause harm. Since we don't yet have a definitive
test that can tell the difference, and may not for many years, most
prostate cancer experts believe that this cancer is now not only over
diagnosed but also over treated.
Does the PSA test save lives -- according to the American Cancer
Society, 28,000 men died from prostate cancer in 2008 -- or does it
merely subject a large number of men with elevated PSAs to unnecessary
surgery or radiation with side effects that can include urinary
incontinence, erectile dysfunction, and irritative urinary and bowel
symptoms? Doctors and patients alike have always wanted to know the
answer for years, and they were hoping that these randomized trials
would provide them. Unfortunately, they did not.
According to H. Ballentine Carter, M.D., Director of Adult Urology at
the Brady Urological Institute at Johns Hopkins, the studies will not
end the controversy surrounding the PSA test, a blood test that millions
of men have been taking since it was first introduced in the late 1980s.
It's currently estimated that 25 million PSA tests are performed
annually in the United States."I am not sure that we learned a
tremendous amount from the NEJM studies," admits Dr. Carter. "We already
knew that we were over diagnosing and over treating this disease. Now we
have numbers to document the extent of over treatment."
The studies published in the NEJM, from large randomized studies
performed in North America and Europe, yielded contradictory results. An
early analysis of the North American study of 77,000 men aged 55 to 74,
which is still ongoing, showed no reduction in death from prostate
cancer attributable to prostate cancer after seven to 10 years of
follow-up.
However, the European study of 182,000 men aged 55 to 69, which is also
ongoing, showed a 20% reduction in death among men who had PSA testing.
For every life saved, however, 1,400 men need to be screened and 48
would need treatment following a positive PSA and digital rectal exam to
result in one fewer death during a 10-year period.
Another way to look at it: 47 men who had a PSA test followed by surgery
or radiation for their cancer may not have needed it, and many might go
on to have urinary and erection complaints. In harming their quality of
lifethat this is too high price to pay for a disease that was not going to
cause harm.
However, further follow-up could demonstrate a greater benefit of PSA
screening and reduced harm as we learn more about the ability of PSA
testing to prevent other outcomes, such as the development of metastatic
disease and local progression of cancer that requires treatment. In
addition, since prostate cancer takes a long time to progress, the 20%
reduction in prostate cancer mortality found after 10 years could be
higher with longer follow-up. "PSA screening is certainly not perfect, but it is clearly saving some
lives," says Dr. Carter. "If an individual is thinking about being
tested, we now have some numbers to give him and he can make up his mind
whether or not to be tested. If a man wants to continue to be tested,
that's certainly reasonable." Once a man knows the risks and the trade-offs, he may or may not want to
have a PSA test. "Americans are not like Europeans," concedes Dr.
Carter. "We tend to be aggressive about wanting to know more. In spite
of these new reports, I still think most men will still want to have the
PSA test."
In light of these new studies, what should a man do? Says Dr. Carter: "I
like what Dr. Michael J. Barry, M.D., medical director of the John D.
Stoeckle Center for Primary Care, said in his NEJM editorial about the
studies. He wrote, "The implications of the trade-offs reflected in
these data, like beauty, will be in the eye of the beholder. Some
well-informed clinicians and patients will still see these trade-offs as
favorable; others will see them as unfavorable. As a result, a shared
decision-making approach to PSA screening, as recommended by most
guidelines, seems more appropriate than ever."
Bottom line: What the studies point out is that right now we still don't
have a one-size-fits-all type test. While Dr. Carter believes that the
value of the PSA test is still debated, until we have a better biomarker
test that can differentiate inconsequential from lethal tumors, the PSA
test needs to be used more judiciously. "I think a lot of the
overtreatment we see has to do with using PSA as an absolute cutoff. I
think PSA velocity, how fast the PSA moves over time, may be a better
measure of the presence of lethal cancer. "Doctors can get a lot more information if there is a PSA history, which
is why I believe getting a baseline PSA at a younger age is a reasonable
thing to do.," says Dr. Carter. "I recommend that all men should have an
initial PSA test starting at age 40. A follow-up test should be given at
age 45 and then again at age 50. Combining that information with the
patient's age, size of the gland, and the free PSA test, should improve
the accuracy of the PSA test. This will indicate their risk of
developing prostate cancer. "While not precise, it offers the best indication we have so far about
the presence of cancer and what should be done," he says.
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If you'd like to continue this important "conversation" with Dr.
Carter, we invite you to subscribe to The Johns Hopkins Prostate
Bulletin which Dr. Carter writes along with Dr. Jacek L. Mostwin and Dr.
Alan W. Partin. The Johns Hopkins Prostate Bulletin is an indispensable
quarterly journal for men with prostate cancer and the other prostate
health concerns, including benign prostatic hyperplasia (BPH) and
prostatitis. It also deals with side effects and related conditions,
such as lower urinary tract symptoms (LUTS), overactive bladder, and
erectile dysfunction.
You'll find that The Johns Hopkins Prostate Bulletin goes beyond the
basics to report on the latest therapeutic treatments, advanced news of
clinical trials, in-depth reports, new medications, plus detailed
answers to subscribers' concerns about all aspects of your prostate
health. |