Prostate
Cancer Supplement Contaminated
An
herbal mixture that was widely used for the treatment of prostate cancer,
but is no longer on the market, was contaminated with synthetic drugs.
That
is the conclusion of a new study in the Journal of the National
Cancer Institute.
The
mixture, called PC-SPES, started being used in late 1996 and early 1997,
says study author Dr. Robert Nagourney. It was sold as a dietary supplement
"for prostate health," but was widely used to treat prostate cancer.
Early
Results Were Promising
In
the beginning, the mixture looked good, Nagourney says, who heads Rational
Therapeutics Inc., a research and therapy institute focusing on alternative
treatments.
"We
were seeing genuine responses," he says. Patients with advanced prostate
cancer were seeing a decline in their levels of PSA (prostate-specific
antigen), a marker for the disease.
"But
patients, meantime, were complaining of breast tenderness," Nagourney
says.
To
investigate, Nagourney and his co-workers obtained eight lots of PC-SPES,
manufactured at different times between 1996 and last year, and analyzed
them. They found all lots contaminated with indomethacin, a pain reliever,
and most with diethylstilbestrol, a potent synthetic estrogen that accounted
for the breast tenderness. Later, warfarin, a blood thinner, began appearing
in the herbal mix.
Nagourney
and his colleagues originally presented the information in April at
a meeting of the American Association for Cancer Research.
The paper in the recent Journal of the National Cancer Institute
issue provides more detailed analysis.
Was
the contamination by the manufacturer, BotanicLab, which has since gone
out of business, accidental or deliberate?
Contamination
Not Likely An Accident
Nagourney
says he cannot tell for sure. However, he adds that it seems "highly
improbable" the drugs would get there accidentally, especially since
one is a potent pain reliever and prostate cancer patients are often
in pain, and another a potent estrogen, a treatment that had been used
in prostate cancer treatment in previous years. Warfarin is a blood
thinner that counteracts the effects of estrogen, such as an increased
likelihood of blood clots.
While
Nagourney's team has no plans to put together another PC-SPES formula,
"we have redoubled our efforts to identify compounds for the treatment
of prostate cancer," he says. "We anticipate we will have some such
product available in the future."
About
189,000 new prostate cancer cases will be diagnosed in the United States
this year, according to American Cancer Society estimates,
and 30,200 men will die of the disease.
A
Lesson To Be Learned
Meanwhile,
Dr. Jeffrey D. White, director of the Office of Cancer Complementary
& Alternative Medicine at the National Cancer Institute,
calls the contamination a "lesson" for future dietary supplement research.
"Herbal
research is complicated enough without having to deal with the added
problem of potential product adulteration," he writes in an accompanying
editorial in the journal.
Consumers
Beware
Consumers
should be aware that such problems can exist, White says. "Don't just
expect these products should have undergone the same testing as [prescription]
drugs." Since they are regulated as dietary supplements, they do not
undergo the same rigorous review.
White
praises the Nagourney study as "a very complete, careful analysis of
several lots of the product, rather than looking at just a couple of
recent lots."
Before
deciding to use a dietary supplement for cancer treatment—or other
health problems—patients should talk to their physician and get
as much information as possible, White and Nagourney agree.
Always
consult your physician for more information.
Online
Resources
American
Association for Cancer Research
American
Cancer Society
American
Urological Association
National
Cancer Institute
National
Cancer Institute, Office of Cancer Complementary and Alternative Medicine
National
Human Genome Research Institute
Nature
Genetics
US
Food and Drug Administration (FDA)
|
October
2002
Early
Results Were Promising
Contamination
Not Likely An Accident
A
Lesson To Be Learned
Consumers
Beware
Gene
Mutation May Be Linked to Prostate Cancer
Online
Resources
Find
a St. John's Mercy Physician
In
Other Men's Health News:
Gene
Mutation May Be Linked to Prostate Cancer
Finding
opens doors to potential treatments
Scientists
have discovered another genetic clue that may eventually help physicians
treat or even prevent prostate cancer.
The
researchers have isolated a gene mutation they believe might play
a role in the development of prostate cancer following infection
of the gland. The gene, MSR1, a macrophage scavenger receptor, shows
mutations in a significant percentage of men with prostate cancer,
as well as in families where prostate cancer is hereditary, the
researchers say.
MSR1
has previously been linked to the formation of arterial plaques
that lead to heart disease, although these findings do not yet suggest
a conclusive connection between prostate cancer and arterial plaques,
the researchers say.
"We
don't want to give people the impression this has immediate impact
on how we manage prostate cancer," says William Isaacs, professor
of urology and oncology at the Brady Urological Institute and Kimmel
Cancer Center at Johns Hopkins University.
"However,
this broadens our thinking about what may cause prostate cancer
and how the body reacts and recognizes the process of prostate cancer
formation," he says.
MSR1
helps white blood cells, called macrophages, clean up cellular debris
from bacterial infections and damaged fats or lipids. Macrophage
activity is known to increase in the early stages of prostate cancer,
and the researchers suspected that some MSR1 mutations might inhibit
the ability of macrophages to clean up properly after prostate infections,
which produce inflammatory lesions that are often early markers
of prostate cancer.
The
novelty of this finding is that it is the first time this gene has
ever been implicated in a cancer, Isaacs says.
In
clinical practice, physicians already closely monitor prostate infection
as a precursor to prostate cancer.
"Men
often have infections in the prostate," says Dr. Timothy Thompson,
professor of urology at Baylor College of Medicine in Houston. "However,
the way the immune system reaction to infection develops into cancer
is not straightforward," he says.
Thompson
adds that in previous studies of macrophage activity in prostate
cancer, macrophages sometimes seemed to be beneficial, engulfing
prostate cancer cells to kill them. At other times, they seemed
to assist cancer cells.
"If
the macrophages persist in the prostate, it's probably because there
are one or more cancer cells that are resistant. The cancer cells
can then use factors secreted by the macrophages to survive and
grow more virulent. If these interactions between macrophages and
cancer cells are allowed to persist, they could set the stage for
cancer," Thompson says.
The
new findings were the result of collaborative efforts by researchers
from Johns Hopkins University, Wake Forest University, and the National
Human Genome Research Institute.
The
study was published online yesterday in the journal Nature
Genetics.
Isaacs
notes that the current research looked only at men of African and
European descent, leaving open future inquiry into Hispanics, Asians,
and other populations.
Always
consult your physician for more information.
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