UICC World Cancer Congress 2006

Methods: The world's publications were reviewed to search for science-based evidence relevant to the relationship between green tea and cancer.

Results: Green tea has been reported to be an effective anticancer agent in prevention and in treatment (Shanafelt TD et al. Leukemia Research 2005:Nov 30 Epub ahead of print). Both experimental and epidemiological data published in the world literature appear to validate the pharmacodynamics calculation of the US National Cancer Institute (J Cellular Biochem 26S:236-257, 1996) that the lowest effective anticancer dose per day for an average person is 800 ml of green tea that contains 710mcg/ml (-)-epigallocatechin gallate (EGCG), the “typical” green tea traditionally valued as medicinal beverage in Asia. However, most commercial green tea leaves marketed in the US, in the United Kingdom and in Asia do not yield this strength of EGCG concentration when the customary 1:100 leaf-to-water ratio is used to brew tea drinks. Failure of consumer access to high EGCG green teas might have accounted for the lack of anticancer effects of green tea in some human populations. Green tea leaves must contain at least 7.1% EGCG if they are used for preparing medicinal beverage, especially in the fight against cancer. In addition to chemoprevention, green tea may be considered as a science-based anticancer agent in formulating non-toxic therapeutic regimens, or as a supplement to boost the anticancer effects of conventional chemotherapeutic drugs.