Prostate Cancer Screening and Early Detection
Last Revised June 20, 1997.
Introduction |
Recommendations for prostate cancer testing |
Should you have regular prostate cancer tests? |
Patient advice and consent
Introduction
It is easy to get confused about the difference between screening
for prostate cancer and early detection of the disease. It
happens to professionals and to patients. Let's see if we can get the
difference clear.
Let's say that Dr Brown, a urologist, decides to try and find how many
men in Brownsville have prostate cancer. He decides that to do this he
will randomly give a free digital rectal examination (DRE) and PSA test
to every man over 50 years old who walks past his office on main street
on a Saturday morning in May. In other words, these men are picked
completely at random -- except that they must walk past his office and
be over 50. This is a prostate cancer screening program. The
men don't necessarily even think that they should be having a prostate
cancer test.
On the other hand, the next year, Dr Brown decides just to offer a free
DRE and PSA test to any man over 50 who comes to his office on the same
Saturday morning in May and asks for one. So he puts an ad in his local
Brownsville newspaper. This year, the people who get the DRE and the
PSA test have selected themselves for some reason. Maybe they
just think its time they had a PSA test. Maybe they have had to get up
a few times too often in the middle of the night. Maybe their wife told
them it was high time they had a prostate cancer test. Or maybe they
just thought that they'd have a test while it was free. Urologists now
tend to call this case finding. It certainly isn't screening.
The test is not being given at random because the men have selected
themselves.
Finally, the third year, Dr Brown decides he isn't going to give
anything away for free. Instead, he will encourage every man over 50
who comes to his office to have a DRE and a PSA test, regardless of
their symptoms. His justification for this is that if they have come to
see him -- a urologist -- there is good reason to think that they may
have a urological disorder, including prostate cancer. This is true
early detection. In other words, Dr Brown is going to do his
best to find prostate cancer in any patient who comes to see him, but he
isn't going to go out of his way to find patients with the disease.
Recommendations for prostate cancer testing
There is no information yet available that can tell us whether screening
for prostate cancer makes any difference whatsoever to how long a
patient will live after his prostate cancer is discovered. In other
words, we don't know if early detection makes a difference. This is
something many people are working very hard to find out more about. In
this way, prostate cancer is different to breast cancer. In the case of
breast cancer it was proved several years ago that regular screening of
patients using self examination and mammograms to detect breast cancer
early did indeed make a difference to the survival of at least some patients with this
disease.
A major clinical trial currently being carried out by the National
Cancer Institute (the so-called PCLO trial) has, as one of its
objectives, the determination of whether prostate cancer screening will
increase patient survival. However, it will be several years before the
results of this trial are known, and some people are not convinced that
the way this trial has been organized will allow us to find the
information we are looking for.
Relatively recently, one government report published by the Office of
Technology Assessment of the US Congress has suggested that Medicare
should pay for regular prostate cancer examinations for all eligible
men. This should make eligible men very happy, since it will save them
from paying for these tests. On the other hand, if every eligible man
decided to get these test every year, it would cost a small fortune --
millions and millions of dollars. Can we afford this?
Wesley Eastridge, MD, a primary care physician in Tennessee, has put
together an excellent assessment on the Web of the differing recommendations of
many medical and healthcare organizations on the value of PSA testing in
screening and early detection of prostate cancer. Dr Eastridge's materials,
PSA? Prostate cancer screening,
obviously represent his personal opinions and are primarily intended for
physicians. However, they also offer an important resource for interested
patients.
Recommendations of the US Preventive Services Task Force:
In its December 1995 revision to its guidelines on effective
disease prevention and health promotion (Guide to Clinical
Preventive Services, 2nd edition, 1995), the US Preventive
Services Task Force has indicated that there is no current evidence
to support annual PSA testing and DRE examinations for men over
50 years of age. This does not mean that men with possible symptoms
of prostate cancer should not be tested. It does mean that a large
sector of the medical community will not endorse annual PSA tests and DREs
for asymptomatic males. The Prostate Cancer InfoLink is of the opinion
that it will require proof of an association between early disease detection
and increased overall survival to change the recommendations of the
US Preventive Services Task Force.
Recommendations of the American College of Physicians:
The American College of Physicians (one of the largest organizations of
primary care physicians in the US) published a series of detailed articles
on prostate cancer in the Annals of Internal Medicine in early
1997. They made two specific recommendations in their clinical guidelines on
screening:
- Recommendation 1: Rather than screening all men for prostate cancer
as a matter of routine, physicians should describe the potential benefits and
known harms of screening, diagnosis, and treatment; listen to the patient's
concerns; and then individualize the decision to screen.
- Recommendation 2: The College strongly recommends that physicians help
enroll men in ongoing studies.
This second recommendation is a specific reference to the PLCO screening
trial previously mentioned and the PIVOT trial (discussed elsewhere).
Recommendations of the American Urological Association:
The American Urological Association (the AUA) is the national
organization representing most of the urologists in America. This group
currently makes the following recommendations regarding regular testing
for prostate cancer:
- All males of 50 years or more should have an annual prostate
examination comprising a digital rectal examination and a PSA test.
- All males of 40 years or more with a family history of prostate
cancer should have an annual prostate examination comprising a digital
rectal examination and a PSA test.
Recommendations of the American Cancer Society:
The American Cancer Society (ACS) has issued guidelines which fall in between those of
the ACP and the AUA on prostate cancer screening. According to the ACS,
beginning at age 50,
an annual prostate examination, including a digital rectal examination
and a PSA test, should be offered annually to men who have a life expectancy of
at least 10 years, and to younger men who are at high risk. The
ACS emphasizes the benefits of beginning annual screening at age 45 in
certain high-risk populations (e.g., African-American men and men with
two or more first-degree relatives with prostate cancer).
Should you have regular prostate cancer tests?
As indicated in the recommendations of the US Preventive Services task force,
and despite the recommendations of the AUA and the ACS, there are many
physicians who do not believe that annual PSA tests are necessarily a
good thing. They argue that while it may be possible to find
indications of possible prostate cancer using digital rectal
examinations and PSA tests, the really hard questions are How hard
must we then search to discover whether a particular patient actually
has prostate cancer? and then How do we treat his disease when we
find it?
An option that some men consider is annual digital rectal examinations
without PSA testing. While there is a good chance that such tests will
allow an experienced urologist to detect clinically significant prostate
cancer, it is also true that by the time a digital rectal examination
becomes a certain indicator of probable prostate cancer, it may not be
possible to apply potentially curative therapy with confidence.
Ultimately the decision whether you should have regular tests for
prostate cancer -- and what those tests should be -- is a matter for you
and your physician. The answer is likely to require careful assessment
of your personal attitudes to the risks of cancer, family history of
cancer, age, and your other clinical history. The Prostate Cancer
InfoLink encourages you to talk frankly with your primary care physician
about this and to make your decision only when you feel comfortable
about it.
Patient advice and consent
Because prostate cancer testing is controversial, some centers have decided to give
formal advice to a patient about this, and request patient's consent to test or not to test for
prostate cancer. The Prostate Cancer InfoLink considers that this is an interesting and
possibly a useful approach. The advice and consent form developed by Gerald Chodak, MD, can be
seen if you click here.
Equally, the American College of Physicians has specifically recommended that
all men who are considering having a digital rectal examination and a PSA measurement
should be fully informed as follows:
- Prostate cancer is an important health problem.
- The benefits of one-time or repeated screening and aggressive treatment of
prostate cancer have not yet been proven.
- Digital rectal examination and PSA measurement can both have false-positive
and false-negative results.
- The probability that further invasive evaluation will be required as a
result of testing is relatively high.
- Aggressive therapy is necessary to realize any benefit from the discovery of
a tumor.
- A small but finite risk for early death and a significant risk for chronic illness,
particularly with regard to sexual and urinary function, are associated
with these treatments.
- Early treatment may save lives.
- Early detection and treatment may avert future cancer-related illness.
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