By Maggie Fox, Health and Science Correspondent
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.
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.