Rudolf Steiner was a weird guy by any stretch of imagination. He was the founding father of anthroposophy, an esoteric “philosophy” that created a new dimension of obtrusiveness. Not only that, he also dabbled in farming methods, devised an educational technique and created an entire school of health care, called anthroposophical medicine. The leading product in its range of homeopathy-inspired “drugs” is a mistletoe-extract which is, according to Steiner, a cure for cancer. His idea was simple: the mistletoe plant is a parasite that lives off host trees sapping its resources until, eventually, it might even kill its host – just like cancer threatening the life of a human being!!!
So, what is more logical than to postulate that extracts from mistletoe are a cure for cancer? Medicine seems simple – particularly, if you do not understand the first thing about it!
But here comes the odd thing: some ingredients from mistletoe do actually have anti-cancer properties. So, was the old Steiner an intuitive genius who somehow sensed that mistletoe would be a life-saver for cancer patients? Or is all this just pure luck? Or was it perhaps predictable?
Many plants produce molecules that are so toxic that they can kill (cancer) cells, and many conventional cancer drugs were originally derived from plants; the fact that mistletoe has some anti-cancer activity therefore comes as a surprise only to those who have little or no knowledge of phyto-pharmacology.
Ok, mistletoe might have some ingredients which possess pharmacological activity. But to claim that it is a cancer cure is still a huge leap of faith. This fact did not stop promoters of anthroposophical medicine to do just that.
Due to decades of clever promotion, it is now hard in many countries (including for instance Germany) to find cancer patients who have not tried mistletoe; indeed, selling mistletoe preparations to desperate cancer patients has become a mega-business.
But does it actually work? Do these extracts achieve what proponents advertise?
The claims for mistletoe are essentially twofold:
1) Mistletoe cures cancer.
2) Mistletoe improves the quality of life (QoL) of cancer patients.
The crucial question clearly is: are these claims based on good evidence?
According to our own systematic review, the answer is NO. In 2003, we looked at all the clinical trials and demonstrated that some of the weaker studies implied benefits of mistletoe extracts, particularly in terms of quality of life. None of the methodologically stronger trials exhibited efficacy in terms of quality of life, survival or other outcome measures. The current Cochrane review (of which I am not a co-author) concluded similarly : The evidence from RCTs to support the view that the application of mistletoe extracts has impact on survival or leads to an improved ability to fight cancer or to withstand anticancer treatments is weak.
But both reviews have one major weakness: they included all of the many available extracts of mistletoe – and one cannot deny that there are considerable differences between them. The market leader in this area is Weleda (avid readers of science blogs might remember that this firm has been mentioned before); they produce ISCADOR, the mistletoe extract that has been tested more than any other such preparation.
Perhaps it would be informative to focus specifically on this product then? A German team from the “Center for Integrative Medicine, Faculty of Health, University of Witten/Herdecke” has done just that; despite the fact that these authors are not really known for their critical analyses of anthroposophical medicine, their conclusion is also cautious: The analyzed studies give some evidence that Iscador treatment might have beneficial short-time effects on QoL-associated dimensions and psychosomatic self-regulation.
So, what is the bottom line? Sceptics would say that almost a century of research without a solid proof of efficacy is well and truly enough; one should now call it a day. Proponents of mistletoe treatment, however, insist: we need more and better studies. Well, there is more! A new RCT of Iscador has just been published.
It included chemotherapy-naive advanced non-small-cell lung cancer (NSCLC) patients to assess Iscador’s influence on chemotherapy-related adverse-effects and QoL. Patients with advanced NSCLC were randomised to receive chemotherapy alone or chemotherapy plus Iscador thrice weekly until tumour progression. Chemotherapy consisted of 21-day cycles of carboplatin combined with gemcitabine or pemetrexed. Seventy-two patients were enrolled of whom 65% were in stage IV, and 62% had squamous histology. Median overall survival in both groups was 11 months. Median time to tumour progression was not significantly different between the two groups. Differences in grade 3-4 haematological toxicity were not significant, but more control patients had chemotherapy dose reductions, grade 3-4 non-haematological toxicities, and hospitalisations.
The authors’ conclusion: No effect of Iscador could be found on quality of life or total adverse events. Nevertheless, chemotherapy dose reductions, severe non-haematological side-effects and hospitalisations were less frequent in patients treated with Iscador, warranting further investigation of Iscador as a modifier of chemotherapy-related toxicity.
So, does Steiner’s notion based on the weirdest of intuitions contain some kernel of truth? I am not sure. But for once I do agree with the proponents of mistletoe: we need more and better research to find out.