March 28, 2000 (Tampa, Fla.) -- Herbal and plant preparations long used in Asian cultures are becoming popular with advocates of natural remedies in the West, and are often taken without the advice of a physician. Now researchers say that people who use these substances may be on to something. Some, such as the Japanese maitake mushroom and a mixture of eight Chinese herbs called PC-SPES, have been shown in early studies to be effective in treating bladder, prostate and gastric cancers.
The gargantuan maitake mushroom has been used for food and medicine in China since the Han dynasty (202 B.C. to A.D. 220). Maitake means "dancing mushroom." The rare fungus also grows in North America, where it is known as "hen-of-the-woods." It can grow to a weight of 100 pounds and 20 inches in diameter.
Denis Miller, MD, global clinical manager with Aventis Pharmaceuticals in Bridgewater, N.J., discussed the mushrooms this week at the American Cancer Society's annual Science Writers Seminar, which explored alternative medicine.
He described studies in which researchers looking for the mushroom's active ingredients extracted a group of substances called polysaccharide B-glucans. They administered the B-glucans to mice that had been given tumors, and found that they reduced the tumors' size by 80%. Further studies appear to show that B-glucans stimulate the immune system, and may be of protective and therapeutic value in treating cancers.
"My own sense is that ... this interesting compound is worthy of further investigations," said Miller, who researched maitake mushrooms while serving as scientific director of the Cancer Treatment Research Foundation.
The maitake extract is readily available as 100 mg capsules in health food stores. There appear to be minimal side effects.
Eating the mushrooms, which have a woodsy, chicken-like flavor, may not give the same benefit as capsules. "You know what you'd need to do to get the same amount [of B-glucans] in the animal models?" Miller asks WebMD. "It was like 5% of total caloric nutritional intake was mushroom. Now, you may be the greatest gourmand in the world and you might love mushrooms, but that's a lot of mushrooms."
People hearing of maitake's benefits are going to take it, Miller says, but he issues a word of caution. As with any herbal or vitamin dietary supplement, people should let their doctors know they're taking it -- particularly if they are cancer patients.
PC-SPES is another preparation that is showing promise for cancer patients, particularly those with prostate cancer. Abraham Mittelman, MD, who spoke about the herbal compound at the conferences, says his interest in the substance was piqued by a discovery a few years ago.
"My involvement with PC-SPES began three years ago when two of my patients with prostate cancer came to see me and they were getting better, but not from the treatment that I was providing," Mittelman says. "After a while I got information they were taking PC-SPES." Mittelman is associate professor of medicine and associate director of oncology at Westchester Medical Center in Valhalla, N.Y.
Studies in rats showed that this herbal blend seems to be effective for prostate cancer. A small study of patients with advanced prostate cancer showed a reduction in protein specific antigen (PSA) levels that lasted well over a year. Elevated PSA levels can indicate the presence of cancer.
"The interesting thing about PC-SPES is that it's an all-or-none response," Mittelman says. "Patients will respond within seven to 14 days. If that does not happen, the patient is not going to respond."
PC-SPES can carry serious side effects, including vein inflammation (phlebitis), and blood clots in the lungs (pulmonary embolism). While the risk of such side effects is small, physicians need to be aware their patients are taking the herbal compound, Mittelman says.
The bottom line, Mittelman and Miller agree, is that physicians should be involved in any decision to use these remedies.
"Share the information with your physician -- keep open communication," Miller says. "If you're a cancer patient and you're taking a nutritional adjuvant, let your doctor know about it."
- A study on mice has shown that an extract taken from the Japanese maitake mushroom can reduce tumor size by 80% and stimulate the immune system.
- Another alternative preparation, known as PC-SPES, may be effective against prostate cancer, but in a few patients it causes serious side effects.
- With all alternative remedies, patients should talk with their physicians about what they are taking.