Together with a co-worker, Prof Walach conducted a systematic review of mistletoe extracts (Rudolf Steiner’s anti-cancer drug) as a treatment for improving the quality of life (QoL) of cancer patients. They included all prospective controlled trials that compared mistletoe extracts with a control in cancer patients and reported QoL or related dimensions.
Walach included 26 publications with 30 data sets. The studies were heterogeneous. The pooled standardized mean difference (random effects model) for global QoL after treatment with mistletoe extracts vs. control was d = 0.61 (95% CI 0.41-0.81, p < 0,00001). The effect was stronger for younger patients, with longer treatment, in studies with lower risk of bias, in randomized and blinded studies. Sensitivity analyses supported the validity of the finding. 50% of the QoL subdomains (e.g. pain, nausea) showed a significant improvement after mistletoe treatment. Most studies had a high risk of bias or at least raise some concern.
The authors concluded that mistletoe extracts produce a significant, medium-sized effect on QoL in cancer. Risk of bias in the analyzed studies is likely due to the specific type of treatment, which is difficult to blind; yet this risk is unlikely to affect the outcome.
This is a surprising conclusion, not least because – as reported on this blog – only a year ago another German team of researchers conducted a similar review and came to a very different conclusion. Here is their abstract again:
Purpose: One important goal of any cancer therapy is to improve or maintain quality of life. In this context, mistletoe treatment is discussed to be highly controversial. The aim of this systematic review is to give an extensive overview about the current state of evidence concerning mistletoe therapy of oncologic patients regarding quality of life and side effects of cancer treatments.
Methods: In September and October 2017, Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL and “Science Citation Index Expanded” (Web of Science) were systematically searched.
Results: The search strategy identified 3647 articles and 28 publications with 2639 patients were finally included in this review. Mistletoe was used in bladder cancer, breast cancer, other gynecological cancers (cervical cancer, corpus uteri cancer, and ovarian cancer), colorectal cancer, other gastrointestinal cancer (gastric cancer and pancreatic cancer), glioma, head and neck cancer, lung cancer, melanoma and osteosarcoma. In nearly all studies, mistletoe was added to a conventional therapy. Regarding quality of life, 17 publications reported results. Studies with better methodological quality show less or no effects on quality of life.
Conclusions: With respect to quality of life or reduction of treatment-associated side effects, a thorough review of the literature does not provide any indication to prescribe mistletoe to patients with cancer.
How can this discrepancy be explained? Which of the reviews is drawing the correct conclusion? Here are some relevant details that could help finding an answer to these questions:
- Walach is a psychologist by training, while the senior author of the 2019 review, Jutta Huebner, is an oncologist.
- Huebner included only randomised clinical trials (RCTs), whereas Walach included any interventional and non-interventional prospective controlled study.
- Huebner included 17 RCTs that reported QoL data, while Walach included 26 publications with 30 data sets including 5 non-randomised studies.
- Several of the primary studies had been published multiple times at different stages of completion. Walach included these as independent data sets, while Huebner included each study only once.
- Huebner looked at QoL, whereas Walach also considered measurements of self-regulation as outcome measures.
- Both reviews point out that the methodological quality of the primary studies was often poor; Walach drew a positive conclusion regardless, while Huebner did not and pointed out that studies with better methodology show less or no effects on quality of life or side effects of cancer therapy.
- Walach’s review was funded by funded by the Förderverein komplementärmedizinische Forschung, Arlesheim, Switzerland, a lobby group for mistletoe therapy, while Huebner’s work was funded by the German Guideline “S3 Leitlinie Komplementärmedizin in der Behandlung von onkologischen PatientInnen (Registernummer 032-055OL)” funded by the German Cancer Aid (Fördernummer 11583) within the German Guideline Program in Oncology and by the working group Prevention and Integrative Oncology of the German Cancer Society.
I am sure there are other important differences, but the ones listed above suffice, I think, to decide which of the two papers is trustworthy and which is not.
Mistletoe treatment of cancer patients was the idea of Rudolf Steiner. Mistletoe grows on a host tree like a parasite and eventually might kill it. This seems similar to a cancer killing a patient, and Steiner – influenced by the homeopathic ‘like cures like’ notion – thought that mistletoe should thus be an ideal treatment of all cancers. Despite the naivety of this concept, it somehow did catch on, and mistletoe has now become the number one cancer SCAM in Europe which is spreading fast also to the US and other countries.
But, as we all know, the fact that a therapy lacks plausibility does not necessarily mean that it is clinically useless. To decide, we need clinical trials; and to be sure, we need rigorous reviews of all reliable trials. Two such papers have just been published.
The aim of the systematic review was to give an extensive overview about current state of research concerning mistletoe therapy of oncologic patients regarding survival, quality of life and safety.
The authors extensive literature searches identified 3647 hits and 28 publications with 2639 patients were finally included in this review. Mistletoe was used in bladder cancer, breast cancer, other gynecological cancers (cervical cancer, corpus uteri cancer, and ovarian cancer), colorectal cancer, other gastrointestinal cancer (gastric cancer and pancreatic cancer), glioma, head and neck cancer, lung cancer, melanoma and osteosarcoma. In nearly all studies, mistletoe was added to a conventional therapy. Patient relevant endpoints were overall survival (14 studies, n = 1054), progression- or disease-free survival or tumor response (10 studies, n = 1091). Most studies did not show any effect of mistletoe on survival. Especially high quality studies did not show any benefit.
The authors concluded that, with respect to survival, a thorough review of the literature does not provide any indication to prescribe mistletoe to patients.
The aim of the second systematic review by the same team was to give an extensive overview about the current state of evidence concerning mistletoe therapy of oncologic patients regarding quality of life and side effects of cancer treatments. The same studies were used for this analysis as in the first review. Regarding quality of life, 17 publications reported results. Studies with better methodological quality showed less or no effects on quality of life.
The authors concluded that with respect to quality of life or reduction of treatment-associated side effects, a thorough review of the literature does not provide any indication to prescribe mistletoe to patients with cancer.
In 2003, we published a systematic review of the same subject. Here is its abstract:
Mistletoe extracts are widely used in the treatment of cancer. The results of clinical trials are however highly inconsistent. We therefore conducted a systematic review of all randomised clinical trials of this unconventional therapy. Eight databases were searched to identify all studies that met our inclusion/exclusion criteria. Data were independently validated and extracted by 2 authors and checked by the 3rd according to predefined criteria. Statistical pooling was not possible because of the heterogeneity of the primary studies. Therefore a narrative systematic review was conducted. Ten trials could be included. Most of the studies had considerable weaknesses in terms of study design, reporting or both. 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. Rigorous trials of mistletoe extracts fail to demonstrate efficacy of this therapy.
As we see, 16 years and 18 additional trials have changed nothing!
I therefore think that it is time to call it a day. We should stop the funding for further research into this dead-end alley. More importantly, we must stop giving false hope to cancer patients. All that mistletoe therapy truly does is to support a multi-million Euro industry.
“When orthodox medicine has nothing more to offer” is the title of an article by Dr Elizabeth Thompson, a UK medical homeopath. The article was written years ago, but it is still an excellent example for disclosing the dangerously false and deeply unethical reasoning used by many alternative practitioners. The notion that all sorts of disproven treatments like homeopathy are justified when orthodox medicine has nothing more to offer is so very prevalent that I decided to do this post analysing it.
In the following, you see the most relevant sections of Dr Thompson’s original article (in normal print) and my brief comments (in brackets and in bold):
…Some people come when conventional treatments can no longer offer them anything to save their lives. This is a frightening time for them and although the homeopathic approach may not offer a cure at this late stage of their illness (Is she implying that, in some cases, homeopathy can cure cancer?), it can often offer hope of a different kind. (Surely, one does not need homeopathy for giving patients hope). Sometimes it helps people to outlive the prognosis given to them by months or even years. (A prognosis is not a precise time of death; it is based on statistics and therefore depicts a likelihood, not a certainty. Thus patients outlive their prognosis all the time regardless of treatments.) Sometimes it helps them need less (less than what? there is no control group and therefore the statement seems nonsensical) in the way of conventional medicine including pain killers and offers them continuing support despite progressive disease (is she trying to say that in conventional medicine patients with progressive disease do not get continuing support?).
As a doctor working in both conventional and complementary cancer care I have learned the importance of integrating these two perspectives (the integration of unproven therapies into EBM can only render the latter less effective). Ideally the doctor practising homeopathy would work as an integral part of a much wider team which would include family members, nurses, general practitioners, oncologists, surgeons, palliative physicians and other complementary therapists (the concept of a multi-disciplinary team for cancer is one from conventional medicine where it has long been routine). It is disappointing sometimes to see that other healthcare professionals can be unsupportive of a person’s desire to use complementary therapies and for some people the knowledge that the team is not working together can cause doubt and insecurity (for the majority of patients, however, it might be reassuring to know that their oncology-team is evidence-based).
Some patients come at the beginning of their diagnosis wanting to support their bodies with gentler (homeopathic remedies are not gentler, they are ineffective) approaches and help themselves recover from some difficult and powerful treatments such as chemotherapy and radiotherapy (Why are they being told that alternative therapies are effective in achieving these aims when there is no good evidence to show that this is true? Isn’t that unethical?). As well as using homeopathic medicines (no good evidence of effectiveness!!!), the GHH also has experience in using Mistletoe which is given by injection and has been shown to stimulate the group of white cells whose numbers can be depleted during chemotherapy and radiotherapy (also no good evidence that it works clinically!!!).
Other patients come when they have finished most of their treatments but may still not be feeling well despite being given the all clear by their doctors (same again: no good evidence!!!)…
One wonderful aspect of the homeopathic approach is that it can be a very important opportunity to help someone re-evaluate their life and their health (We don’t need to prescribe placebos for that, this aim is better reached by employing a clinical psychologist).
Sometimes hurts in the past have never been healed and sitting with someone as they describe difficult experiences can be itself therapeutic. Combining this therapeutic listening time with substances from nature that gently stimulate the body’s own healing potential (where is the evidence for that claim?) can be an approach that through patient demand and research (what research?) we can demonstrate is really worth offering to many more people…
END OF QUOTE
This text shows in an exemplary fashion how desperate patients can be convinced to make dramatically wrong choices. If you read Dr Thompson’s text without my comments, it probably sounds fairly reasonable to many people. I can understand why patients and carers end up thinking that homeopathy or other disproven therapies are reasonable options WHEN ORTHODOX MEDICINE HAS NOTHING MORE TO OFFER.
But the claim of homeopaths and others that mainstream medicine has, in certain cases, nothing more to offer is demonstrably wrong. Supportive and palliative care are established and important parts of conventional medicine. To deny this fact amounts to a lie! The implied scenario where a patient is told by her oncology team: “sorry but we cannot do anything else for you”, does quite simply not exist. The argument is nothing else but a straw-man – and a vicious one at that.
Moreover, the subsequent argument of homeopaths, “as ‘they’ have given you up, we now offer you our effective homeopathic remedies”, is not supported by good evidence. In other words, one lie is added to another. To call this unethical, would be the understatement of the year, I think.
Cancer patients are understandably desperate and leave no stone unturned to improve their prognosis. Thus they become easy prey of charlatans who claim that this or that alternative therapy will cure them or improve their outlook. One of the most popular alternative cancer therapies is mistletoe, a treatment dreamt up by Rudolf Steiner on the basis of the ‘like cures like’ principle: the mistletoe plant grows on a host tree like a cancer in the human body. One of many websites on this subject, for instance, states:
- integrates with conventional cancer treatments
- can be used for a wide range of cancers
- may be started at any stage of the illness….
- Improved quality of life
- generally feeling better
- increased appetite and weight
- less tired/more energy
- reduced pain
- better sleep pattern
- felling more hopeful and motivated
- reduced adverse effects from chemo and radiotherapy
- reduced risk of cancer spread and recurrence
- increased life expectancy.
Mistletoe extracts have been shown in studies to:
- stimulate the immune system
- cause cancer cell death
- protect healthy cells against harmful effects of radiation and chemotherapy.
In fact, the debate about the efficacy of mistletoe either as a cancer cure, a supportive therapy, or a palliative measure is often less than rational and seems never-ending.
The latest contribution to this saga comes from US oncologists who published a phase I study of gemcitabine (GEM) and mistletoe in advanced solid cancers (ASC). The trial was aimed at evaluating: (1) safety, toxicity, and maximum tolerated dose (MTD), (2) absolute neutrophil count (ANC) recovery, (3) formation of mistletoe lectin antibodies (ML ab), (4) cytokine plasma concentrations, (5) clinical response, and (6) pharmacokinetics of GEM.
A total of 44 study participants were enrolled; 20 were treated in stage I (mistletoe dose escalation phase) and 24 in stage II (gemcitabine dose escalation phase). All patients had stage IV disease; the majority had received previous chemo-, hormonal, immunological, or radiation therapy, and 23% were chemotherapy-naïve.
Patients were treated with increasing doses of a mistletoe-extract (HELIXOR Apis (A), growing on fir trees) plus a fixed GEM dose in stage I, and with increasing doses of GEM plus a fixed dose of mistletoe in stage II. Response in stage IV ASC was assessed with descriptive statistics. Statistical analyses examined clinical response/survival and ANC recovery.
The results show that dose-limiting toxicities were neutropenia, thrombocytopenia, acute renal failure, and cellulitis, attributed to mistletoe. GEM 1380 mg/m2 and mistletoe 250 mg combined were the MTD. Of the 44 patients, 24 developed non-neutropenic fever and flu-like syndrome. GEM pharmacokinetics were unaffected by mistletoe. All patients developed ML3 IgG antibodies. ANC showed a trend to increase between baseline and cycle 2 in stage I dose escalation.
6% of patients showed a partial response, and 42% had stable disease. Of the 44 study participants, three died during the study, 10 participants requested to terminate the study, 23 participants progressed while on study, one terminated the study due to a dose limiting toxicity, 6 left due to complicating disease issues which may be tied to progression, and one voluntarily withdrew.
An attempt was made to follow study subjects once they terminated study treatment until death. At the last attempt to contact former participants, three were still alive and five others were lost to follow-up. The median time to death of any cause was approximately 200 days. Compliance with mistletoe injections was high.
The authors explain that a partial response rate of 6% is comparable to what would be expected from single agent gemcitabine in this population of patients with advanced, mostly heavily pretreated carcinomas. The median survival from study enrollment of about 200 days is within the range of what would be expected from single agent gemcitabine.
The authors concluded that GEM plus mistletoe is well tolerated. No botanical/drug interactions were observed. Clinical response is similar to GEM alone.
These results are hardly encouraging but they originate from just one (not particularly rigorous) study and might thus not be reliable. So, what does the totality of the reliable evidence tell us? Our 2003 systematic review of 10 RCTs found that none of the methodologically stronger trials exhibited efficacy in terms of quality of life, survival or other outcome measures. Rigorous trials of mistletoe extracts fail to demonstrate efficacy of this therapy.
Will this stop the highly lucrative trade in mistletoe extracts? will it prevent desperate cancer patients being misled about the value of mistletoe treatment? I fear not.
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.