Cancer is a major cause of death globally, leading to nearly one in six deaths each year. Several traditional treatments are available for cancer. However, they can cause adverse side effects which deteriorate people’s quality of life. In such scenarios, the effectiveness of complementary treatments like mistletoe can be of interest.
Mistletoe is a semiparasitic plant that has been used as a traditional medicine in Europe for centuries.
The first use of mistletoe as a cancer treatment was proposed by Rudolf Steiner in 1920.
Mistletoe helps in cancer treatment by showing antitumor activity as well as improving the patient’s quality of life.
Further research is required to understand how mistletoe impacts people with cancer.
What is a mistletoe?
Mistletoe is a semiparasitic plant which extracts have been used for centuries to treat several human diseases along with cancer.
It has been used in different forms for the treatment of various diseases such as hypertension, headache, epilepsy, asthma, infertility, menopausal symptoms, and dermatitis.
Mistletoe is capable of growing on several types of trees. The chemical composition of the extracts depends on:
- Species of the host tree
- Time of the year when the tree was harvested
- Preparation of the extracts
- The commercial producer
Mistletoe extract – composition and usage:
Mistletoe extracts are made either in water-based solutions or solutions of water and alcohol. Some extracts are made as per homeopathic preparations, while others are not.
The main active compounds found in mistletoe are:
- Phenolic acids
- Fatty acids
These active compounds help to mediate the pharmacological activities of mistletoe extracts.
Administration of mistletoe extracts mostly takes place by subcutaneous injections, which are given 2–3 times a week. However, the duration of treatment is variable.
Side effects of mistletoe extracts
The side effects of mistletoe extracts are limited and not life-threatening. A few of the side effects include:
- Soreness at the injection site
- Swelling of lymph nodes
However, a few cases of severe side effects such as anaphylactic shocks have been reported.
Mistletoe plants and berries can also be poisonous to humans.
Moreover, high doses of recombinantly-produced mistletoe lectins were reported to cause reversible hepatotoxicity in a few cases.
How mistletoe can help treat cancer
Research suggests that mistletoe extract can can help to treat cancer in various ways. It was demonstrated that the extract can kill cancer cells through the down regulation of genes involved in malignancy, progression of cancerous tumors, as well as cell invasion and migration.
Moreover, mistletoe extract can fight cancer through modulation of the immune system activation of dendritic cells, activation of natural killer cells, increase in cytokine secretion, as well as enhancement of humoral and cellular responses.
The mistletoe extract can also inhibits angiogenesis. This helps to prevent the formation of new blood vessels, which in turn can inhibit the growth of tumors.
Above mentioned anticancer properties of mistletoe are mostly mediated by two active compounds, lectins and viscotoxins.
- Lectins are proteins that easily bind to carbohydrates, in this way they are able to attach to the cell's surface and cause biological changes in them.
- Viscotoxins are proteins that have both immune system-stimulating and cell-killing properties.
Does mistletoe extract treat cancer effectively?
Extensive research has been carried out regarding the impact of mistletoe extract on cancer. Findings from more than 50 clinical trials have been published concerning the use of mistletoe extract in cancer patients.
Most of these studies indicated an improvement in the quality of life of the patients.
A systematic review of 26 studies reported an improvement in fatigue, emotional well-being, depression, vomiting, concentration, and nausea.
Another systematic review also reported improvement in chemotherapy-associated fatigue along with other quality-of-life measures.
A 2020 study also indicated mistletoe extract to improve physical functioning, insomnia, and cancer-related fatigue in 319 non-metastasized breast cancer patients.
However, most of these studies consisted of one or more limitations.
On the contrary, a two-part review indicated that mistletoe extract did not show any improvement in the quality of life and survival of patients with various types of cancer.
Therefore, the use of mistletoe extract for the treatment of cancer patients is controversial. Some studies have shown it to have beneficial effects, while others have shown it to have little or no beneficial effects.
More studies aimed at improving the current limitations are needed to understand whether mistletoe extract should be considered as a treatment option for cancer patients.
Legal aspects of mistletoe extract cancer therapy
Mistletoe extract is an extensively studied alternative cancer therapy that is commonly used for the treatment of cancer patients in Europe. However, it is not approved for treatment in the United States.
Many studies have reported that mistletoe extract can be useful to improve quality of life, survival rates, and cancer-related fatigue in cancer patients.
However, few studies have also reported no positive or beneficial effects of mistletoe extract. Therefore, is it important to consult an oncologist before taking mistletoe extract for the treatment of cancer.
Where to buy mistletoe for cancer?
Mistletoe extracts are mostly used to treat cancer in German-speaking countries. A few of the commercially available formulations of European mistletoe include Iscador, Plenosol, Helixor, Eurixor, abnobaVISCUM, Iscucin, and Isorel.
It is worth mentioning that, mistletoe extracts are not sold in the United States since they have not been approved by the Food and Drug Administration (FDA).
- National Cancer Institute. Mistletoe Extracts (PDQ®)–Health Professional Version.
- Archives of Pharmacal Research. Biological activity of mistletoe: in vitro and in vivo studies and mechanisms of action.
- Integrative Cancer Therapies. Impact of Oncological Therapy and Viscum album L Treatment on Cancer-Related Fatigue and Internal Coherence in Nonmetastasized Breast Cancer Patients.
- Journal of Cancer Research and Clinical Oncology. Mistletoe in oncological treatment: a systematic review : Part 1: survival and safety.
- Journal of Cancer Research and Clinical Oncology. Mistletoe in oncological treatment: a systematic review : Part 2: quality of life and toxicity of cancer treatment.
- World Health Organization. Cancer.