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Conquer Cancer Health News |
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Study: Surprise Effect of Herbs in Prostate Cancer
NEW ORLEANS (Reuters)
When
patients started coming to Dr. William
Oh with tales of an "ancient Chinese
remedy" that helped their prostate
cancer, he was skeptical.
After all, he had seen patients who took
aged garlic, shark cartilage, selenium and
other unproven supplements on their
own, as well as more accepted home remedies such as
vitamin E.
"Ninety-nine percent of this stuff is not going to work,"
Oh said in an interview.
But when their lab tests showed their prostate specific
antigen (PSA) levels were falling -- a sign that their
cancer was being controlled somewhat -- he sat up and
listened.
Oh, a researcher at Boston's Dana-Farber Cancer
Institute, was already doing clinical trials of vaccines and
drug therapies for prostate cancer. So he enrolled some
of the men taking the supplement, sold under the name
PC-SPES, in a trial funded by the nonprofit organization
CapCure.
He presented his findings over the weekend to a meeting
in New Orleans of the American Society of Clinical
Oncology, a meeting of 22,000 cancer specialists from
around the world.
The capsule they were taking is called PC-SPES (PC
for prostate cancer, and SPES from the Latin word for
hope). Patented by BotanicLab, a privately held
company in Brea, California, it is based on a Chinese
formula.
It contains saw palmetto, sold over-the-counter to relieve
some of the prostate symptoms suffered by men as they
age such as the need to urinate more frequently, as well
as licorice, which the company says helps breathing and
digestion.
HERBS USED IN CHINESE MEDICINE
It also contains 6 herbs used in Chinese medicine -- reishi,
the stem of a plant said to "support" the immune system;
Baikal skullcap, the root of a plant meant to remove
toxins; rabdosia, the leaf of a plant that, according to the
company, "promotes healthy cell function;" Dyers woad,
another leaf; mum, a flower; and Panax ginseng, a root.
Oh treated 23 patients whose prostate cancer had not
responded to standard hormone therapy, which involves
chemical or surgical castration to stop the supply of male
hormones that fuel many cases of prostate cancer.
Half of them saw a 50 percent drop in their PSA levels
after several weeks of taking 6 PC-SPES capsules a day.
This was no small improvement.
"This group of patients has few treatment choices," Oh
said. "Average survival is a year, a year and a half at
most."
Two of the patients have since died of their prostate
cancer, and Oh stresses that he did not do research to
see if patients' overall survival was improved.
Dr. Eric Small of the University of California San
Francisco had a similar experience. "Patients were
coming to us, singing its praises, saying 'Doc, you have
got to see this'," Small said in an interview.
He wanted the herbal remedy held to the same standards
as mainstream drugs, so he tested 70 patients, 33 who
had responded to standard hormone therapy, and 37
who had not. Their ages ranged from 43 to 89 years.
All of the patients with cancer that had responded to
hormone therapy had a decline of at least 50 percent in
their PSA levels. Just over half, 54 percent of the
non-responsive group also saw a similar decline.
"After 57 weeks, everyone who got PC-SPES is still
responding," Small said. "Both Dr. Oh and I are pretty
convinced that it has efficacy in hormone-resistant
patients."
They said it is not clear how the compound might be
working, or which elements of it might be working.
POSSIBLE UNIQUE ESTROGEN
"It's possible that it is a unique estrogen that we don't
know about yet," Oh said. Estrogens, the so-called
female hormones, are found in many plants and can
counteract the effects of male hormones in disease.
"It could be a dose effect -- it is possible (PC-SPES) is
giving more of something that was going to work anyway.
It could be there is a new agent in there that hasn't been
identified yet," Oh added.
Much more study will be needed because so many
different compounds are in the blend. And experts rely
most strongly on studies in which patients get treated
randomly and in which neither the doctor not the patient
knows who is getting the experimental therapy and who is
getting standard therapy.
Meanwhile, the capsules are being sold with little mention
of the side-effects, which range from nipple tenderness to
blood clots, which Small saw in four percent of his
patients.
PC-SPES is governed by the U.S. Dietary Supplement
Health and Education Act (DSHEA) of 1994, which is
more lenient than rules governing prescription drugs
because of arguments that herbs have been shown by
centuries of use to be safe.
That any controlled trials were done at all shows the shift
in attitude by doctors, who, for the most part, scoffed at
alternative medicines until recently.
"It was the patients that prompted this," Oh said. "You
learn from your patients. They can teach you a lot of
things."
Even if the supplements themselves turn out not to be that
useful, Oh said they could offer valuable insights into
treating cancer -- perhaps into new estrogens that could
be developed to help patients.
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