May 28 2010

Shark Cartilage – No Benefit for Lung Cancer

Shark Cartilage has long been an alternative cancer treatment – very typical in that it has a shaky but superficially compelling theoretical basis, not empirical support, but plenty of anecdotes to lure the desperate. Promoters claim that sharks do not get cancer, because of anti-cancer properties of their cartilage. However – sharks do get cancer.

Proponents further claim that shark cartilage (and other cartilage products, like bovine cartilage) increase immune activity, kill cancer cells, and prevent angiogenesis – the formation of new blood vessels to feed tumors. None of these properties have been demonstrated, however.The anti-angiogenesis theory is at least plausible – but the simple fact is, if this potential were there a pharmaceutical company would have isolated, purified, and produced a drug based upon the cartilage long ago – with proven efficacy. There has been some interesting basic science, but nothing that has led to an effective drug. And what is on the market is mostly “crude extracts” – nothing but snake oil.

Despite years of use, and millions of dollars spent by cancer patients on dubious cartilage products, the evidence has been solidly negative. So negative, in fact, that we can confidently conclude that shark cartilage is probably not an effective treatment for any type of cancer. There is certainly no justification for its use, which has led to several very negative outcomes: a decline in shark populations, worse outcomes for cancer patients who delayed or ignored proven treatments due to the false promises of shark cartilage, and a vast waste of resources, mostly diverted to people of dubious credibility and motivations.

If we lived in a more rational world, that would be the end of it – but we don’t. So we need to waste money doing further research, going way beyond due diligence, just to serve the irrational beliefs of a subset of the public. That is, in fact, largely what the National Center for Complementary and Alternative Medicine does, which is why they funded (along with the National Cancer Institute) a study of shark cartilage in non-small cell lung cancer.

The study was a double-blind placebo controlled trial with 379 subjects of standard therapy + placebo vs standard therapy + AE-941 (a brand of shark cartilage).  You can read the details in the linked abstract – suffice it to say the results were dead negative. There was no benefit.

Sure – this is just one study of one type of cancer. Cancer is a category of disease, not one disease. I am not saying this should be sufficient to abandon any particular treatment. However, this is just the latest in a long line of negative studies of shark cartilage. When is enough enough?

Even if there are researchers who want to explore this further, that is fine. But there is certainly no justification for a market for shark cartilage for cancer. If anything meets the definition of snake oil, this does. I think we can also conclude that any country that claims to have effective regulation of health products that protects their citizens from worthless or harmful products or false claims, should not allow the sale of shark cartilage for cancer. In other words – we do not have effective regulation of health products. Some people believe that we do not need such regulation, which is a political/ideological opinion they are welcome to. But I think we can objectively say – we don’t have it.

I am glad to have this new evidence to combat the true-believers and snake-oil promoters. But scientific evidence needs to be coupled, in my opinion, with effective regulation, otherwise we are just talking to ourselves.

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