According to a BBC headline today, the Cochrane Collaboration says that:
Homeopathy 'eases cancer therapy'
Wow. The Cochrane Collaboration, the very embodiment of evidence-based medicine, says that homeopathy works! That would really be something to write home about. If it were true. What a recent Cochrane Review, Homeopathic medicines for adverse effects of cancer treatments, in fact concluded was that:
This review found preliminary data in support of the efficacy of topical calendula for prophylaxis of acute dermatitis during radiotherapy and Traumeel S mouthwash in the treatment of chemotherapy-induced stomatitis. These trials need replicating. There is no convincing evidence for the efficacy of homeopathic medicines for other adverse effects of cancer treatments. Further research is required.
In other words, they found two high-quality positive trials. One of them, the trial of "Traumeel S", included just 30 patients, 15 on placebo and 15 on the homeopathic treatment. Which is not very many. Still, at least it actually was a trial of a homeopathic treatment. The other positive trial, the one on "topical calendula", wasn't.
No, really. The second trial, a fairly large French study (254 patients), used an ointment made from a herb, Calendula officinalis, aka the Pot Marigold. Unlike homeopathic treatments, which are just water, the Calendula ointment used in the study in question was apparantly
fabricated^ from a plant of the marigold family, Calendula officinalis.^ The digest is obtained by incubation at 75°C in petroleum^ jelly to extract the liposoluble components of the plant.
In other words, it contained plenty of chemicals from the plant, and would be better described as a herbal product, not a homeopathic one. Unlike in a homeopathic remedy, the herb wasn't diluted in water several times until no molecules of the original product remained. It's not homeopathy. The word "homeopathy" doesn't appear anywhere in the paper!
So why on earth was this study included in the Cochrane Review? This is where things get weird. The Cochrane authors describe the paper as "a study of a homeopathic ointment". But how did they even hear about the paper, given that the word homeopathy appears nowhere in the paper, or the abstract, or the PubMed keywords? They say that "One potential study was identified by an expert in the field (Pommier 2004)."
So the best evidence that homeopathy works for alleviating the symptoms of cancer therapy is a paper that isn't about homeopathy, identified by "an expert" in homeopathy. And the Cochrane Collaboration took his word for it. And the BBC reported on it as fact (although to their credit they do include a scathing comment from Prof. Edward Ernst.) A great job all round!
If anyone has any ideas about why this paper was included in the Cochrane review, I'd be interested to hear them. I will be in contact with the authors of the review to try to find out why, because if the Cochrane Collaboration has really just published a review about homeopathy which includes a trial which is nothing to do with homeopathy, it's something of a scandal. I find it somewhat hard to believe just on the basis that Cochrane reviews are generally very competent. So, stay tuned for more on this.
Update 18 4 2009: The authors have kindly responded to my email.