Green tea is once again in news, this time for its promise shown as cancer prevention agent in oral cancer patients diagnosed with a pre-malignant condition known as oral leukoplakia.
The researchers at the University of Texas M.D. Anderson Cancer Center, who examined the effectiveness of green tea as a chemo-preventative agent in high-risk patient population, for their study on Cancer Prevention Research, found that more than half of the oral leukoplakia patients who consumed the extract showed promising results.
Being rich in polyphenols, green tea exhibits carcinogenesis in preclinical models. Although it is still very early to confirm this fact, and there is no definite proof that green tea is an effective preventive agent, the results are a definite encouragement to study more about patients at highest risk for oral cancer, says Vassiliki Papadimitrakopoulou, M.D., Professor in Andersons Department.
The main attraction about green tea is the lack of toxicity in prevention trials, and the trials were performed on otherwise healthy individuals, Vassiliki said.
In the phase II of the study carried out between August 2002 and March 2008, the participants were given either green tea or placebo. The participants took the extract, an oral agent for three months at one of three doses “ 500 mg/m2, 750 mg/m2 or 1000 mg/m2 thrice a day. The participants underwent baseline and 12-week biopsy, an important component in the design of the study.
It was found that among those taking green tea at two highest doses, 58.8 percent showed a clinical response, compared to 36.4 percent in the lowest extract dose, and only 18.2 percent in the placebo.
The other significant findings were that the green tea extract improved histology and helped in improving the number of biomarkers that could play a lead role in predicting cancer development. The extract was well tolerated, although mild symptoms of insomnia and nervousness were seen in high-dose group, but with no toxicity.
According to the American Cancer Society, about 35,720 or more people are likely to be diagnosed with oral and/or pharynx cancer and the five-year survival rate is less than 50 percent.