by Tri D. Do, MD, MPH
August 2002
Lighthouse Community Center Newsletter
I usually go to my doctor once a year for the prostate
exam. But now I've been reading that these examinations are not as
necessary as they used to be. What is the guideline now used? I hear
there is a scoring system from 1-5 for the blood test results.
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Contrary to what we’ve all been told, science rarely has exact answers.
Within the medical profession, we often say that the practice of medicine
is more like an art form where judgment and intuition are just as important
as knowledge. Even with the best set of guidelines, it sometimes feels
more like finger-painting than MOMA masterpieces. A good physician
will treat each person individually, on a case-by-case basis. Recommendations
for cancer screening, then, are just recommendations — and not hard-and-fast
rules. The expert scientific bodies and professional societies of medicine
may disagree on their guidelines, leaving clinicians who practice medicine
on the front lines wondering what to do.
The American Cancer Society is one such organization that publishes guidelines
on prostate cancer screening. They, along with the American Urological
Association, have stated that doctors should offer yearly PSA (prostate-specific
antigen) testing to certain men. They also recommend a yearly digital
rectal examination (DRE), which really has nothing to do with cyber sex—it’s
the much-beloved part of the physical exam where the doc inserts a gloved
finger into your bum and checks to see if the prostate feels abnormal.
However, the American College of Physicians and many other groups have looked
at the scientific data around screening. They argue against
screening for prostate cancer with either PSA or DRE, and they say that
there is too much harm and not enough benefit. These are highly respected
organizations of generalists and specialists, too—the big daddies of the medical
world, just so you know that this is one of the most controversial areas
in primary care.
Let’s take a few steps back and start at the basics here. Cancer
screening is a way to detect cancer early. The assumption is that for
those who have hidden cancers, if we catch it early enough, we can do something
about it. But is this true all the time? Or at all? We
know that screening for breast cancer and cervical cancer definitely save
lives. However, most prostate cancers are slow-growing. Many
of the men diagnosed with prostate cancer will live 10-20 years and never
be bothered by it. In fact, a third of men over the age of 70 have
prostate cancer, but most will die of other causes before the cancer ever
becomes a real problem. For that reason, some folks suggest that only
men with a life expectancy of at least 10 years be screened. And while
late stage prostate cancer is rarely curable, some people who are
discovered to have this cancer early on may in fact live longer than not.
But is it much longer? No study has definitely proved that screening,
in and of itself, improves survival.
These tests aren’t perfect either—in fact, they downright stink.
To address your question about a scoring system—we go by the value of the
PSA. Less than 4 ng/ml is “normal”, 4-10 is abnormal but “iffy”, and
greater than 10 is definitely abnormal. Now here’s a big but: some
people with prostate cancer will have normal tests.
And to add to the drama of it all, some people without cancer will
have abnormal tests. For example, some say that ejaculation
will make the PSA higher than it really is. So abstaining from sex for
a few days beforehand (you know you can do it; we believe in you) is recommended.
Other conditions such as enlargement of the prostate (BPH) can also make
the PSA look higher. Probing, from things such as a rectal exam or receptive
anal sex, has not been found to raise the PSA, but why risk it? Having
a false positive test means that a lot people will be subjected to further
probes, biopsies, and blood tests—not to mention a lot of extra worrying—for
nothing. Therefore screening is not only imperfect; it can also be
harmful.
How good a test like the PSA or DRE is depends on who gets screened.
We don’t screen 30-year olds for prostate cancer even though it’s not impossible
for a younger man to get prostate cancer—maybe one in a billion. On
the other hand, it doesn’t make sense to screen one billion people just to
find that one person. So who does it make sense to screen?
The medical organizations that recommend screening for prostate cancer say
we should offer testing to men older than 50 but younger than 69 years of
age. Why 69? Doctors think it’s a cool number. Also, we
know that men of African descent have a prostate cancer risk 34% higher than
those of European descent. For those who have an immediate family member
with this disease or who are African-American, earlier testing is recommended,
starting at 45 years of age. And if you do decide to go for screening,
be sure and ask for both the PSA and DRE. Sometimes one test will
pick up cancer that the other missed.
There are still other tests such as the TRUS (trans-rectal ultrasound),
but most people and their HMOs would rather not pay hundreds of dollars
to have their nether regions pummeled by sound waves emanating from a humming
plastic spatula. Especially when it doesn’t add anything to the PSA
and DRE.
Confused yet? There are no simple answers to your question, but
this is as much truth as we have at the moment. Now don’t go to your
doctor and tell her she’s a quack because she can’t possibly know what’s
best. Despite the confusion, prostate cancer deaths have decreased
during the 1990s. There are many docs who will swear up and down that
screening has worked and has saved the lives of many patients. With
250,000 Americans likely to be diagnosed with it this year, it is the second
leading cause of cancer deaths in men. And, as far as you might be concerned
(assuming you’ve got a prostate)—numbers be darned, you’d probably rather
be safe than sorry. In the end, it boils down to a personal decision
that you should discuss with your physician.
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