Green tea holds promise as a chemopreventive agent of oral cancer, study finds

Green tea extract has shown promise as a way known to prevent cancer of the oral cancer patients with pre-malignant conditions such as oral leukoplakia, according to researchers at the University of Texas MD Anderson Cancer Center.

The study, which is online in Cancer Prevention Research, the first investigating green tea as a chemopreventive agent in this population of patients at high risk. The researchers found that more than half of patients receiving oral leukoplakia occurs, the extract showed a clinical response.

Long in the laboratory, epidemiological and clinical settings for multiple forms of cancer, green tea polyphenols, which are known to inhibit carcinogenesis in preclinical models with success. However, clinical results have been mixed from.

"Although it is still early, and no definitive proof that green tea is an effective preventive agent to promote these results certainly study for patients with high risk of oral cancer," said Vassiliki Papadimitrakopoulou, MD, professor in MD Anderson's Department of Thoracic / Head and Neck Medical Oncology, and lead author of the study. "extract the lack of toxicity is interesting - in the prevention studies, it is very important to remember that these people are healthy, and we must ensure that the agents studied produced no harm. "

In the phase II dose-finding study, 41 patients had oral leukoplakia MD Anderson between August 2002 and March 2008 were randomized to receive either the green tea extract or placebo. The participants adopted the extract an agent orally for three months at three doses - 500 per meter of body weight (mg / m 2); squared 750 mg / m 2 or 1,000 mg / m 2 - three times a day. To judge the best biological markers subject to the subscriber base and also a 12-week biopsy, an important element in designing the study, researchers say.

"It was the collection of oral tissue biopsies is essential that we learn that not only the green tea extract appears useful for some patients, but we refer to the anti-angiogenic effects as a potential mechanism action, "said Anne Tsao, MD, assistant professor in the Department of Thoracic / Head and Neck Medical Oncology, and the first author of the study." During the first, because our patient population was so small, this which gives direction to further study. "Among them, green tea in the two highest doses were 58.8 per cent achieved a clinical response, compared to 36.4 percent, the lowest dose of extract and 18.2 percent in the placebo arm. In an extended follow-up, with an average of 27.5 months, 15 participants had developed oral cancer, with a median time to development of 46.4 months.

Although not statistically significant, the green tea extract also improved histology, and an improvement in a number of biomarkers, which may have tended to play an important role in predicting cancer progression.

Another important finding researchers say, is that the extract was well tolerated. Side effects, including insomnia and nervousness have been observed mainly in the group receiving the highest dose, but no significant toxicity.

"Although similar results, are encouraging, further research remains to be done before we can be that green tea May prevent oral or any other type of cancer. It is also important to people that this study included participants very little to remember is that at higher doses the equivalent of eight cups of green tea three times a day, "said Papadimitrakopoulo. "We need to better understand where green tea effects of long-term prevention for patients."

Papadimitrakopoulo Tsao and believe that future studies should concentrate with green tea in this population at high risk for participants, where the award is exposed for a longer period. The researchers also noted that green tea has been investigated in this study had never sold more than extracts of OTC and / or the Internet, which is not strictly regulated. Instead, the connection has been developed exclusively as a drug.

Expected, according to American Cancer Society, over 35,720 of them will be diagnosed with oral and / or throat cancer and the survival rate at five years is less than 50 per cent.