Shark Cartilage Doesn’t Work Against Cancer

It was1983 when the first signs that shark tissue might have anti-cancer effects emerged.  The discovery was followed by an enthusiasm for shark cartilage therapy in helping treat inoperable or untreatable cancer cases.  Millions of dollars were spent over the next decade on doubtful sources of shark cartilage, often outside the USA.  Although early clinical trials held out little hope of an anti-cancer effect of the substance, people still wanted to try it ‘as a last resort’ when they had tried everything else.

The final blow against shark cartilage has fallen with a report on a study sponsored by  the National Cancer Institute, and conducted under the control of MD Anderson Cancer Center, University of Texas; it’s published in the Journal of the National Cancer Institute. 

A standardized watery shark cartilage extract was used, which had the properties of blocking blood vessel growth demonstrated in the 1983 studies.  In a randomized, double-blind trial, the shark cartilage or a placebo was given to stage III non-small cell lung cancer patients being treated with chemoradiotherapy.  The study enrolled 379 patients between 2000 and 2006.  The study was closed early because of low accrual of subjects.

There were no statistically significant differences in overall survival, progression-free survival, time to progression, and tumor response rates between the patients taking shark cartilage and those taking placebo.  The authors of the report state:  “This study does not support the use of shark cartilage-derived products as therapy for lung cancer”.  It’s probably the only adequate well-controlled, well-conducted study of shark cartilage since the 1983 reports of its activity in cell cultures.   Which only shows how long it takes to ‘prove a negative’.  Maybe we should be less willing (and/or gullible) to accept results from research that’s preliminary and not representative of the true clinical situation.