How well does Essiac work?
Two reviews exist in the peer-reviewed literature (refs 1,2). Neither has identified a single published clinical trial. The first review, Kaegi et al, discusses the history and safety of Essiac along with laboratory and clinical evidence. The second review by Boon et al reviews the efficacy and safety of various botanical medicines (including Essiac).
""Two reviews exist in the peer-reviewed literature. Neither has identified a single published clinical trial."
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Most of Essiac’s identifiable components have shown anticancerous properties individually. For instance, burdock (Arctium lappa L.) has shown antitumour activity in early studies of animal systems (refs 5,6). Benzaldehyde, which has been isolated from burdock, has shown antitumour activity in some animal tests. More recent studies, however, have shown no such activity (refs 7,8). An antimutation factor was isolated from burdock in 1984, which is resistant to both heat and protein-digesting enzymes (ref 9). The US National Cancer Institute (NCI) (ref 10) tested burdock 14 times, with one sample showing activity, though not considered significant, in the P388 mouse leukaemia model (ref 11).
Certain chemicals in Indian rhubarb (Rheum palmatum L.) have shown antitumour activity in some animal test systems (ref 11,12). The NCI tested two samples of Indian rhubarb from Poland and found no antitumour activity in a mouse leukaemia model.
The NCI tested sheep sorrel (Rumex acetosella L.) for its anticancer activity and found no activity against mouse leukaemia. However, the compound aloe emodin, isolated from sorrel, has previously shown significant antileukaemic activity (refs 13,14).
The NCI has tested slippery elm (Ulmus rubra Muhl) seven times using samples from various parts of the US and found no antitumour activity in mouse leukaemia systems.
Pre-clinical studies
Essiac was tested in a mouse sarcoma model in the US by the Memorial Sloan Kettering Laboratories, New York, in 1959 and again from 1973 to 1976. Difficulties with the test systems arose and the researchers were unable to establish appropriate administration and storage of the herbs. Some preliminary reports, which were never published, suggested some evidence of biological activity but no firm conclusions were reached. The results of six immunotherapy tests and two chemotherapy tests of Essiac samples supplied to the Memorial Sloan Kettering Cancer Center by Caisse, as tested on the mouse sarcoma model, showed no activity.
In 1983, the Resperine Corporation Ltd submitted a liquid Essiac sample to the NCI, which tested it in a mouse lymphocytic leukaemia model. The NCI tested burdock 14 times with one sample. It found that the highest concentrations of Essiac given to the animals during the study resulted in lethal toxicity and no antitumour activity as demonstrated.
An in-vitro study comparing Essiac® and Flor-Essence® in human breast cancer cells found that both of the teas demonstrated antiproliferative and differentiation inducting properties, but this effect was only observed at high concentrations (1/10 and 1/100) (ref 3).
Uncontrolled trials
A Canadian study collected case reports submitted voluntarily by physicians. This case series included 86 patients with advanced cancers who had been treated with Essiac (ref 15). Forty-seven patients received "no benefits", eight of the reports were impossible to evaluate, 17 patients died, one patient experienced ‘subjective improvement’, five required fewer analgesics, four had an ‘objective response’, and four were in ‘stable condition’. All of the patients also received conventional treatment, which could have explained their improvement.
Controlled trials
No such studies are available.
References
1. Kaegi E. Unconventional therapies for cancer: 1. Essiac. The Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative. CMAJ 1998;158:897-902.
2. Boon H, Wong J. Botanical medicine and cancer: a review of the safety and efficacy. Expert Opin Pharmacother 2004;5:2485-501.
3. Tai J, Cheung S, Wong S, Lowe C. In vitro comparison of Essiac and Flor-Essence on human tumor cell lines. Oncol Rep 2004;11:471-6.
5. Foldeak S, Dombradi GA. Tumor-Growth Inhibiting Substances of Plant
Origin. I. Isolation of the Active Principle of Arctium lappa. Acta Phys Chem 1964;10:91- 93.
6. Dombradi CA, Foldeak S. Screening Report on the Antitumor Activity of Purified Arctium Lappa Extracts. Tumori 1966;52:173.
7. Itokawa H, Watanabe K, Mihara K. Screening Test for Antitumor Activity of Crude Drugs (2). Shoyakugaku Zasshi 1982;36:145-9.
8. Woo WS, Lee EB, Chang I. Biological Evaluation of Korean Medicinal Plants. II. Yakhak Hoe Chi 1977;21:177-183.
9. Morita K, Kada T, Namiki M. A desmutagenic factor isolated from burdock (Arctium lappa Linne). Mutat Res 1984;129:25-31.
10. NCI. These data are unpublished, though publicly available from NCI on request.
11. US Congress, Office of Technology Assessment: Unconventional Cancer Treatments. Washington, DC: U.S. Government Printing Office, 1990. OTA-H-405, pp 71-5.
12. Belkin M, Fitzgerald DB. Tumor-Damaging Capacity of Plant Materials. 1. Plants Used as Cathartics. J Natl Cancer Inst 1952;13:139-155.
13. Kupchan SM, Karim A. Tumor inhibitors. 114. Aloe emodin: antileukemic principle isolated from Rhamnus frangula L. Lloydia 1976;39:223-4.
14. Morita H, et al. Cytotoxic and mutagenic effects of emodin on cultured mouse carcinoma FM3A cells. Mutat Res 1988;204:329-32.
15. Henderson IWD. Director, Bureau of Human Prescription Drugs, Health Protection Branch, Health and Welfare Canada, Vanier, Ontario. Letter to J.W. Meakin. Executive Director, Ontario
