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.