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Annual PSA Test May Not be Necessary for All
Prostate cancer is the second leading cause of death for men in the
United States. And while the chance of being diagnosed with prostate
cancer over a lifetime may be as high as 20%, the chance of dying of
prostate cancer is only about 3%. But the risk of prostate cancer increases
with age. More than 75% of all cases occur in men over 65, and about
40% of men over 80 have the disease. When it is diagnosed early, prostate
cancer is more likely to be treated successfully. Cure rates are excellent
for cancer that is discovered and treated when it is still confined to
the prostate gland. About 95% of men with localized prostate cancer treated
by surgery are alive after five years.
The prostate-specific antigen (PSA) test is a primary test for finding
early-stage prostate cancer. PSA is a protein produced by the prostate
gland, and PSA levels become elevated in men with prostate cancer. Although
some respected groups recommend an annual PSA test for all men over age
50, the annual PSA test remains controversial. That is, in part, because
it has a high chance of being falsely negative (20%-40% of men with prostate
cancer have normal levels of PSA) or falsely positive (PSA levels may
be elevated in men with noncancerous prostate conditions).
At a meeting of the American Society of Clinical Oncology, researchers
presented findings that indicated that an annual PSA test may not be
warranted in men over 50 with an initial normal PSA (04 nanograms/milliliter).
For five years, researchers tracked the annual PSA test results of 27,863
men ages 5574 whose PSA levels were initially normal. . They found
that 98.6% of men with a PSA result of less than 1 ng/ml at baseline
would remain negative after 4 more annual tests and that 98.8% of men
with a baseline PSA of 12 ng/ml would have a negative PSA test
the following year.
Based on these results, the researchers concluded that performing a
PSA test every five years on men with an initial PSA less than 1 ng/ml
and every two years for men with a PSA of 12 ng/ml would reduce
the number of PSA tests performed by 55%. This would save money and help
men avoid the anxiety associated with yearly prostate tests.
July 2002 Update
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Caution Always Key in Using Herbal Medicines
A recent study published in the New England Journal of Medicine offers
another important reminder on careful use of herbal remedies. This caution
is rooted in the absence of strict pharmaceutical controls in the manufacture
of such products and how the lack of these requirements can leave room
for tragic errors.
In the mid-1990s, doctors at a clinic in Belgium treated 43 patients
with end-stage kidney failure, requiring dialysis or transplant. Not
surprisingly, these individuals had something in common in their medical
histories. Between 1990 and 1992, each had used a Chinese herbal remedy
in combination with two other drugs for weight loss. The herbal preparation
supposedly contained Stephania tetrandra and Magnolia officinalis.
But the sudden appearance of kidney failure in these patients, caused
their doctors to suspect that the herb Aristolochia fangchi, which
is poisonous to the kidneys, had unintentionally been substituted for S.
tetrandra. The Chinese names for A. fangchi and S. tetrandra sound
similar and the two are often confused. Analysis showed that the herbal
remedy did, in fact, contain aristolochic acids, which are derived from
A. fangchi. Aristolochic acids cause cancer in rats and mutations in
bacteria and mammals.
Reports of patients who had developed urothelial carcinoma (cancer of
the tissues lining the bladder, ureter, and part of the kidney), as well
as kidney failure related to the Chinese herbs, drew concern among the
Belgian doctors. When one of their patients also developed this cancer,
the doctors decided that all patients with end-stage kidney failure related
to the use of Chinese herbs should be checked for cancer of these organs.
By removing these organs, the doctors hoped to prevent cancer from developing
in their patients. Thirty-nine of the 43 patients agreed to undergo the
preventive surgery. Of these patients, 46% of them already had cancerous
growths in the removed tissues. In addition, 19 of the remaining 21 patients
had abnormal growths in the urinary system. The investigators also analyzed
DNA samples taken from the kidneys and ureters of each patient. The DNA
samples for every patient showed changes typically found after exposure
to aristolochic acid. The researchers compared these results to analysis
of DNA samples taken from eight patients with end-stage kidney failure
unrelated to Chinese herbs. None of these control samples showed DNA
changes formed by aristolochic acid.
The doctors calculated the cumulative dose of the implicated herb and
other treatments for each patient. They found that the risk of cancer
was related to the cumulative dose of A. fangchi. Because many
of the patients had also taken appetite suppressants as well as a diuretic,
the doctors noted that these drugs might enhance the toxicity of aristolochic
This case study provides strong evidence suggesting a relationship between
the Chinese herb A. fangchi and urothelial carcinoma. While a
manufacturing mistake led to the introduction of this herb into an herbal
preparation for weight loss, this study highlights the risks involved
in taking herbal remedies. There is little control over the quality of
herbal medicines. This means that the label on an herbal medicine may
not accurately represent what is actually in the container, as was the
case with S. tetrandra. Several countries have banned the use
of herbs that contain aristolochic acid, yet Aristolochia is readily
available in the United States in capsule form.
In the United States, the FDA does not have the authority to assess the
safety and efficacy of a dietary supplement before it reaches the shelves
of stores. The agency is allowed to restrict a supplement only after
it proves the substance is harmful as commonly consumed, but there is
no adequate system for reporting serious side effects associated with
these products. Furthermore, the FDA does not have any way of knowing
which herbal remedies contain harmful substances such as aristolochic
acid. The case of the Chinese herbal diet pill and its association with
urothelial cancer is just one of a number of cases that demonstrate the
need for greater oversight of dietary supplements and caution in the
use of supplements on the part of consumers.
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