A new look at old medicines
CHICAGO: Scientists are studying traditional food supplements used for centuries - from ginseng and flaxseed to shark cartilage - for possible cancer-curing qualities, according to research presented at a major cancer conference in Chicago.
Though the first extensive clinical test on whether shark cartilage, taken with chemotherapy or radiation therapy, has anti-cancer properties, showed no effect in prolonging lung cancer patients' lives, a new study did find that flaxseed can stop the progression of prostate cancer, researchers told the American Society of Clinical Oncology (ASCO).
A diet low in animal fats, however, was not successful in slowing prostate cancer, the research showed.
A pilot study also indicated high doses of ginseng help cancer patients battle fatigue, often a side effect of the disease.
"The use of complementary and alternative medicine to treat cancer and its side effects has been widespread, but there have been few studies designed to scientifically evaluate whether a particular approach is effective," said Dr Bruce Cheson, head of hematology at the Lombardi Comprehensive Cancer Center at Georgetown University in Washington.
Flaxseed is rich in Omega-3 fatty acids, which is also found in some fish, and believed to act on cell membrane production and slow their spread, according to author of the study Dr Wendy Demark-Wahnefried, of Duke University in North Carolina.
Flaxseed also contains a type of hormone called lignans, which can neutralize other hormones such as testosterone or estrogen and could slow cancer cell progression.
The clinical test on 161 prostate cancer patients found that those taking 30 grams of flaxseed a day saw their tumors progress 30-40 percent more slowly than those taking a placebo or on a diet low in saturated fat.
Ginseng, cultivated for centuries in Asia for its root, has grown popular among cancer patients plagued by fatigue. Animal testing showed the energizing effect of ginsenosides, a substance similar to steroids. But ginseng had not been scientifically tested on humans.
This study of 282 cancer patients for two months found that a quarter of those taking 1,000-2,000 mg of ginseng extract daily said they felt better or much better than a control group on a placebo.
Charles Lu, a cancer specialist at the University of Texas at Houston, worked on the shark cartilage study. His results "definitely demonstrate that shark cartilage extract is not effective against lung cancer when combined with chemoradiotherapy."
The negative results "are disapointing", Lu said, "but this study shows the benefit of conducting scientifically rigorous studies on potential anti-cancer agents, including those that some may consider to be alternative therapies."
AFP
(China Daily 06/06/2007 page19)
