WEDNESDAY, Sept. 4, 2002 (HealthDayNews) -- 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's the conclusion of a new study in today's Journal of the National Cancer Institute.
The mixture, called PC-SPES, began to be 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.
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 got 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 today's journal provides more detailed analysis.
Was the contamination by the manufacturer, BotanicLab, which has since gone out of business, accidental or deliberate?
Nagourney says he can't 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.
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 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 doctor and get as much information as possible, White and Nagourney agree.
What To Do
For more information on complementary and alternative medicine treatments, see the National Cancer Institute's Office of Cancer Complementary and Alternative Treatment. For information on prostate cancer, see the American Cancer Society.
