In 2007, we published a systematic review summarizing the efficacy of homeopathic remedies used as a sole or additional therapy in cancer care. We have searched the literature using the databases: Amed (from 1985); CINHAL (from 1982); EMBASE (from 1974); Medline (from 1951); and CAMbase (from 1998). Randomized and non-randomized controlled clinical trials including patients with cancer or past experience of cancer receiving single or combined homeopathic interventions were included. The methodological quality of the trials was assessed by Jadad score. Six studies met our inclusion criteria (five were randomized clinical trials and one was a non-randomized study); but the methodological quality was variable including some high-standard studies. Our analysis of published literature on homeopathy thus found insufficient evidence to support the clinical efficacy of homeopathic therapy in cancer care.
Meanwhile, more trials have emerged, not least a dubious study by Frass et al which is currently under investigation. This means that a new evaluation of the totality of the available evidence might be called for. I am pleased to report that such an assessment has just been published.
In this systematic review, the researchers included clinical studies from 1800 until 2020 to evaluate evidence of the effectiveness of homeopathy on physical and mental conditions in patients during oncological treatment.
In February 2021 a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsychInfo, CINAHL, and Medline) to find studies concerning the use, effectiveness, and potential harm of homeopathy in cancer patients.
From all 1352 search results, 18 studies with 2016 patients were included in this SR. The patients treated with homeopathy were mainly diagnosed with breast cancer. The therapy concepts include single and combination homeopathic remedies (used systemically or as mouth rinses) of various dilutions. Outcomes assessed were the influence on toxicity of cancer treatment (mostly hot flashes and menopausal symptoms), time to drain-removal in breast cancer patients after mastectomy, survival, quality of life, global health and subjective well-being, anxiety, and depression as well as safety and tolerance.
The included studies reported heterogeneous results: some studies described significant differences in quality of life or toxicity of cancer treatment favoring homeopathy, whereas others did not find an effect or reported significant differences to the disadvantage of homeopathy or side effects caused by homeopathy. The majority of the studies have low methodological quality.
The authors concluded that, for homeopathy, there is neither a scientifically based hypothesis of its mode of action nor conclusive evidence from clinical studies in cancer care.
I predict that, if we wait another 15 years, we will have even more studies. I also predict that some of them will be less than reliable or even fake. Finally, I predict that the overall result will still be mixed and unconvincing.
Why can I be so sure?
- Because homeopathy lacks biological plausibility as a treatment of cancer (or any other condition).
- Because highly diluted homeopathic remedies are pure placebos.
- Because homeopathy has developed into a cult where one is no longer surprised to see studies emerging that are too good to be true.