Shark Cartilage Trials

December 16, 2010

People suffering from terminal diseases often grasp at unproven therapies.  For several decades one of these has been shark cartilage, claimed by some to be a cure for cancer.  This idea came originally from the mistaken belief that sharks themselves do not get cancer.  In fact, sharks do get cancer, though strong immune systems mean that sharks develop cancer, and probably other diseases, at a lower frequency than many animals.  Desperate cancer patients, however, believed that if sharks do not get cancer, then eating sharks should be able to cure cancer, and a new folk remedy was born.

Over the past 10 years, numerous clinical trials have tested the ability of shark cartilage products to slow or cure cancer in humans; the vast majority of these have shown no benefit.  Quite the opposite, false hopes based on unproven therapies can keep patients from seeking medically proven treatments that might extend their lives.  There is also an effect on sharks of course.  Millions of sharks are killed each year - for their fins, for their cartilage - and this unsustainable take has led to dramatic declines in virtually every shark species studied.

Recently, scientists at the M. D. Anderson Cancer Center completed the largest clinical trial of shark cartilage ever conducted.  Nearly 400 patients with advanced lung cancer were given either a shark cartilage product, or a placebo, along with their regular chemotherapy.  The patients were followed to assess their survival time and the growth of their tumors.  The study showed that shark cartilage did not slow tumor growth, or prolong survival time, in these patients.

Does this mean that sharks have nothing to teach us about human cancer?  Not at all!  Some shark products have been shown in the laboratory to stop new blood vessels from forming.  Tumors need to make new blood vessels to continue to grow, and so compounds that can halt this process might in fact be used to treat some types of cancer.  But this cannot be accomplished simply by eating a shark.  Rather than killing sharks, we should be studying them.  Learning more about the unique physiology of sharks may help us to prevent and treat human cancer.

The article may be found here: Lu C, et al. 2010. Chemoradiotherapy with or without AE-941 in stage III non-small cell lung cancer: a randomized phase III trial. Journal of the National Cancer Institute. 102:859-865.