Testing To Prevent Cancer
cancer, a phrase once uttered in whispers, is now in the news
almost daily. General Norman Schwarzkopf and more recently New
York mayor Rudy Giuliani are only two of the famous men who have
or have had the disease. They and thousands of others have had
their cancers diagnosed with the help of a PSA test. PSA stands
for "prostate specific antigen," a protein produced in the prostate
gland and released into the blood. (The prostate, a small gland
behind the bladder, produces seminal fluid.) PSA levels are normally
very low, but rise when prostate disorders such as infection,
benign enlargement, or canceroccur. Digital rectal exam
(DRE), usually done at the same time as PSA testing, also helps
detect some cancers, but not as many as the blood test.
The problem, though, is that nobody has ever been able to show
that PSA testing actually saves lives. Do men live longer if they
discover their cancers early and undergo treatment? There is still
no definite proof, via a clinical trial, but the good news has
been slowly accumulating. It now appears that the death rate from
prostate cancer has declined since testing began.
For example, a study by National Cancer Institute researchers
published in March found that for white men, the death rate from
prostate cancer had declined below levels of 14 years ago, when
PSA testing was first approved. (The death rate among African-Americans
has also begun to decline, but not as much.) Among men aged 60
to 79, the death rate was even lower than thatlower than
50 years ago. Some researchers attribute this to PSA testing,
but others disagree. Currently, some official organizations, such
as the American Urological Association, recommend regular PSA
testing for all men over 50. But other experts are less sure of
the benefits and do not recommend routine PSA testing. This newsletter
has recommended it in a limited way. What's behind these differences
of opinion is a complicated story.
Prostate cancer is quite common. Autopsies have shown that 30%
of men over 50 and 70% at age 80 have small prostate cancers that
haven't spread or caused symptoms. But only 3% of men die from
it. In many men the disease does not spread and has few symptoms,
or none. On the other hand, it can be deadlyit kills more
men (32,000 in the U.S. predicted this year) than any other cancer
except lung cancer. And though this is typically an older man's
disease, it sometimes strikes men in their fifties or even younger.
For reasons not wholly understood, African-American men are more
likely to have prostate cancerand also more likely to die
from it than other men.
downside of PSA testing
A simple blood test that can help detect cancer might sound like
a dream come true, but in fact the PSA test detects only high
levels of PSA, not cancer. The only way to tell which men have
cancer and which have some benign disorder is through a surgical
biopsyan expensive and unpleasant procedure. It's estimated
that only about one-third of men with high PSAs turn out to have
cancer. However, in one unpublished study presented recently at
the meeting of the American Urological Association, researchers
at the Washington University School of Medicine in St. Louis reported
that of some 1,500 men undergoing surgical biopsies, only 165
turned out to have cancer. That's just over 10%, which is not
very many, considering the expense, particularly the psychological
expense for the men undergoing testing.
problem: There's no way to predict for sure which cancers
(detected by biopsies) will be aggressive and which will stay
confined to the prostate and cause few or no symptoms.
another: It's possible to have a low PSA and still have
prostate cancer. Indeed, one in five men with prostate cancer
do not have an elevated PSA. Moreover, as we've said, a high PSA
can arise from other disorders, or be elevated for no apparent
another problem: Even if you're diagnosed with prostate
cancer, there's no one best treatment. Surgery to remove the prostate
and/or radiation are standard; but both treatments often produce
such complications as impotence and urinary incontinence. For
older men "watchful waiting" rather than treatment is sometimes
best. This means frequent visits to the doctor for retesting and
examination, with an eye to beginning therapy if the cancer progresses.
Trials are underway to determine whether "watchful waiting" is
better than immediate surgery.
spite of all the drawbacks, millions of men are currently being
tested, and death rates from prostate cancer appear to be declining
markedly. In another recent report to the American Urological
Society, researchers from Italy and Austria reported a big decline
in prostate cancer deaths in the Austrian state of Tyrol, where
PSA screening was offered free to men aged 45 to 75 beginning
in 1993. Two-thirds of all males were screened, and the death
rate plummeted41% below expected levels in 1998. This study
has received a lot of publicity but has not been published, and
there could be many questions about this result. There are currently
two large studies in progress, one in the U.S. and one in Europe.
They are specifically designed to determine whether PSA screening
decreases mortality. Results from this research will be available
beginning in 2006.
We see no reason, therefore, to change our prior recommendations.
Given the advantages and disadvantages of this test, a man should
discuss the issues thoroughly with his physician before being
tested. Here's our advice:
If you are under 50 and have no symptoms of prostate cancer, and
no family history of it, you need not be tested.
If you are African-American or have a family history of prostate
cancer, begin screening at age 50. Some doctors say you should
begin at age 40.
If you are 50 to 75 with no family history or other risk factors,
you may choose not to be screened.
If you are over 75, and symptom-free, you may choose not to
If your PSA level turns out to be high, get retested before
having a biopsy.
If you are taking any drug (such as Proscar) or herbal product
(saw palmetto) for prostate problems, be sure to tell your doctor
before your test, since these products may affect PSA levels.
Reference Source 98,99,101