Herbal Treatment Shows Effectiveness Against Prostate Cancer, Studies Find

American Institute for Cancer Research
Thursday, 31 August 2000

Forty Percent Reductions Seen in Tumor Incidence with Plant Mixture

In both laboratory and clinical observations, a specific mixture of Chinese and American herbs shows promise as an effective treatment for prostate cancer, according to Dr. Jan Geliebter of New York Medical College. In an address at the American Institute for Cancer Research (AICR) 10th Annual Research Conference in Washington, DC, Dr. Geliebter described the promising results observed when prostate cancer is treated with the combination of eight plants known as PC-SPES.

"Treatment with PC-SPES has induced decreases in the PSA (prostate-specific antigen) levels of prostate cancer patients," he said. "It has reduced the occurrence of tumors by approximately 40 percent in animal studies, and demonstrated potent anti-cancer effects in human tissue culture."

Institute Sees Pressing Need for Responsible Study of Complementary Approaches

According to a 1998 Duke University study, 70 percent of breast and prostate cancer patients take some form of dietary supplement. This figure raises concern among physicians and cancer scientists, who stress that very little research has yet been done on the effects of supplement pills and powders, particularly in regard to possible interactions with mainstream cancer treatments.

In the absence of reliable scientific knowledge about the effects of these increasingly popular products, it has been impossible to accurately measure the benefits - and risks - of so-called "alternative" or "complementary" approaches to cancer treatment.

As part of its pressing mission to reduce the worldwide burden of cancer, AICR is dedicated to redefining notions of "mainstream" and "alternative" approaches. To this end, one of AICR's research goals is to fund work that subjects "alternative" approaches to the stringent controls of the scientific method.

Research on Herbal Mixture Spurred by Patients' Word-of-Mouth

Research on PC-SPES is one example. Scientific study of the mixture's effects only began when physicians reported that their prostate cancer patients who were taking the supplements felt better, Dr. Geliebter said. PC-SPES is an over-the-counter food supplement sold as a refined powder containing eight different plant species: Isatis, Licorice, Lucid ganoderma, Pseudo-ginseng, Rubescens, Saw palmetto and Scute.

"Patients told their doctors that they felt great," Dr. Geliebter said, "but you can't measure how much someone may or may not 'feel better.' So, clinical researchers focused on PSA levels, which we can measure."

Subsequent clinical observations have shown that dietary supplementation with PC-SPES does lower levels of PSA (prostate-specific antigen) in patients with prostate cancer. Members of the clinical community began to take note.

PSA levels are widely used to gauge the extent of prostate cancer, but they are only an indicator of the disease. Further tests were needed to confirm that PC-SPES exerted a measurable anti-cancer effect.

Such confirmation is taking shape in a series of laboratory studies performed by Dr. Geliebter and his colleagues, Dr. Tiwari and Dr. Mittelman. A dose of aggressive cancer cells that normally causes lethal tumors in 99 percent of rodent subjects was injected into rats who were being fed diets supplemented with PC-SPES.

Approximately forty percent of these animals experienced no tumors at all. These results offered further support of the herbal treatment's anti-cancer potential, but another variable needed to be ruled out.

"Whenever you test a substance within the body, the immune system's role has to be accounted for. We need to determine how much of the cancer-fighting effects arise from treatment with PC-SPES, and how much from the body's defenses."

Geliebter and his colleagues then turned to tissue culture cells. Their results indicated that extracts of PC-SPES strongly inhibit the growth of prostate cancer cells in culture. Dr. Geliebter finds this new data encouraging, in that it adds to the growing evidence of the mixture's treatment potential. He notes, however, that the research with the most wide-ranging ramifications remains to be done.

Finding the "How and Why"

"The interesting thing about PC-SPES research is that it's proceeded in such an upside-down direction," he said. "It began with humans, and moved into the laboratory.

"Usually, you start in the lab, and only graduate to human studies once you've found out everything you can about the mechanism of a substance's anti-cancer actions. So here we are, with a substance showing real-world potential, and we still don't know precisely why it seems so effective. That's the next step."

While human, animal and tissue studies continue, Dr. Geliebter and his colleagues are investigating the anti-cancer activities of PC-SPES on a molecular level. "Whatever we learn about how and why this particular plant mixture works will help us design even better treatments for patients with prostate and other cancers."

As reliable knowledge about herbal and dietary supplements continues to mount, AICR believes it is vital for cancer patients taking any kind of dietary supplement to communicate that information to their doctor. Consultation with a health-care professional is the best way to keep informed about potentially dangerous supplement-medication interactions.

For more information, or to contact American Institute for Cancer Research, see their website at: www.aicr.org