Binns C, et al. Green tea consumption enhances survival of epithelial ovarian cancer patients. Asia Pac J Clin Nutr 2004;12(Suppl):S116
A cohort of Chinese patients with confirmed epithelial ovarian cancer were recruited and followed for a minimum of three years. Subjects or their close relatives were traced and interviewed using a questionnaire. The number of deaths was obtained and hazard ratios calculated. Increasing frequency and quantity of tea consumption was associated with a longer survival in women with epithelial cell cancer: 109 out of 137 tea drinkers survived to the time of interview, compared with only 77 women still alive among the 157 non-tea drinkers. Compared with non tea-drinkers, the adjusted hazard ratios were 0.6 (95% CI 0.4-0.9) for tea drinkers, 0.3 (95% CI 0.2-0.8) for consumption of at least one cup of green tea per day, 0.4 (95% CI 0.2-0.8) for brewing at least one batch of green tea per day and 0.3 (95% CI 0.2-0.8) for consumption of 500 gms or more dried tea leaf per year.
Comments
Green tea is derived from the tea plant (Camellia sinensis). Green tea is very high in polyphenols with potent antioxidant and antitumor properties. The major polyphenols in green tea are flavonoids (catechin, epicatechin, epicatechin gallate, epigallocatechin gallate, and proanthocyanidins). Epigallocatechin gallate (EGCg) is thought to be the most significant active component in green tea. Other components in green tea include a very small amount of caffeine, theanine, lignins, organic acids, protein and chlorophyll.
Green tea polyphenols are potent antioxidant compounds that have demonstrated significant antioxidant activity, as well as increasing the activity of antioxidant enzymes. Green tea polyphenols block the formation of cancer-causing compounds such as nitrosamines, suppress the activation of carcinogens, and detoxify and trap toxic immune damaging substances. Green tea consumption has been studied in humans and found to be preventive against some forms of cancer--stomach, small intestine, pancreas, colon, lung and breast.
In 1998 a study on green tea in women with breast cancer determined that in stage I and II breast cancer, increased consumption of green tea was associated with less metastasized lymph nodes in premenopausal women and increased progesterone and estrogen status in postmenopausal women (a finding that is associated with less aggressive forms of breast cancer). No benefit was seen in stage III breast cancer patients. In stage I and II patients, there was a 16.7% recurrence rate for those consuming 5 cups or more of green tea (average 8 cups) per day. For those who consumed 4 or less cups per day (average of 2), there was a 24.3% recurrence rate. Disease-free survival was also significantly improved in stage I and stage II breast cancer patients with a greater consumption of green tea.
The current study, although not a randomized clinical trial, and inadequate in providing information about stage of their ovarian cancers, it offers one more encouraging reason to recommend green tea to ovarian cancer patients as part of a management strategy to reduce their risk of recurrence.
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