Ocean Watch

By Susan Scott

Monday, April 19, 1999

Shark cartilage seems
useless against cancer

Does eating shark cartilage ease the symptoms of advanced-stage cancer?

That was the question asked by researchers from the Cancer Treatment Research Foundation, Cancer Treatment Centers of America, in designing a recent study on shark cartilage. The results were published last November in the Journal of Clinical Oncology.

The study was undertaken because, as of 1997, an estimated 50,000 Americans have taken shark cartilage with prescribed cancer treatments or as their only treatment.

Cancer victims are taking shark cartilage in droves because of a popular 1992 book, "Sharks Don't Get Cancer -- How Shark Cartilage Could Save Your Life," by William Lane and Linda Cormac.

This treatment was further made popular in 1993 when the CBS news show "60 Minutes" did a report on Lane's experience with shark cartilage on cancer patients in Cuba.

The problem with all this is that the shark-cartilage-as-cancer-medicine theory was never scientifically tested, a crucial step in medical treatments, traditional or alternative.

Strict rules guide such testing. One is that you must compare the experimental medicine to doing nothing. Saying, "My uncle took it and got better," doesn't count. That's called anecdotal evidence and is unreliable because he may have gotten better anyway.

Similarly, saying, "Since shark cartilage stops tumor growth in the laboratory, eating some will relieve cancer in people," doesn't count either. It's an interesting theory but until it's tested, it's a leap.

Neither anecdotal evidence nor theories are valueless in medical science; they're simply beginnings.

The next step is controlled clinical testing. In other words, when looked at objectively, does the stuff actually work?

In the above study of shark cartilage, conducted according to cancer-research protocol, the answer was no. The researchers concluded that, "Under the specific conditions of this study, shark as a single agent was inactive in patients with advanced-stage cancer and had no salutary effect on the quality of life."

Shark cartilage has been in the world of medicine since the 1950s when it was first used, with some success, to promote wound healing and to treat inflammatory diseases such as arthritis.

In laboratory studies, shark cartilage stops the growth of new blood vessels. Therefore, since the growth of cancerous tumors depends upon the creation of new blood vessels, it's reasonable to believe there may be a link between shark cartilage and a cancer cure. This link, however, if one exists, has yet to be found.

It's easy to understand why people in advanced stages of cancer often turn to unconventional treatments. That's why, in 1992, the National Cancer Institute created the Office of Alternative Medicine, designed to support clinical research of unconventional therapies.

Such research has now shown shark cartilage as a cancer treatment is a waste of money. (It can cost up to $700 per month.) Besides that, the FDA does not regulate it for safety, purity, or contaminants and has not approved it as an anticancer agent. 

Also, this "natural" medicine causes the needless death of countless sharks.

Instead of buying shark cartilage, cancer victims searching for alternatives should check Internet Grateful Med for the latest studies on cancer treatments.

Since cancer doctors and researchers would love nothing better than to find new medicines to help their patients, they continue to test a wide variety of substances.

Hopefully, some will pan out.

Marine science writer Susan Scott's Ocean Watch column
appears Mondays in the Star-Bulletin. Contact her at

E-mail to City Desk

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