Researchers have concluded that shark cartilage powder does not demonstrate antitumor properties and is not an effective treatment for patients with advanced cancer, according to the first scientific review of the substance published in a major peer-reviewed journal. More than 50,000 Americans are estimated to have used the powder because of anecdotal claims about its cancer-fighting abilities.
The study, conducted by Dr. Denis R. Miller and his colleagues under the auspices of the Cancer Treatment Research Foundation, examined 60 patients with various advanced cancers who were given three daily doses of shark cartilage for a 3-month periodthe time period conventionally used to evaluate other phase II anticancer agents. Although the shark cartilage was not associated with any serious adverse effects, the study found that none of the patients exhibited any response, complete or partial, to the therapy. Among the patients taking shark cartilage, 79% experienced tumor progression and 21% had stable disease (neither progression nor regression).
Shark cartilage powder has been recently popularized as a cancer remedy, in part, because of preliminary studies showing that certain shark cartilage isolates are antiangiogenic agentsie, they block the growth of tiny new blood vessels that feed tumors. These isolates (which are the subject of ongoing research) are not the same as the dry, pulverized crude form of shark cartilage that is commonly sold in health food stores and supermarkets and is promoted through advertisements, books, the media, and web sites.