Green tea may help protect against oral cancer
An article published in the November 2009 issue of Cancer Prevention Research suggests a protective effect from green tea against the progression of oral lesions that are at high risk of developing into cancer.
A team led by Vassiliki Papadimitrakopoulo, MD, who is a professor of medicine at the University of Texas MD Anderson Cancer Center’s Department of Thoracic/Head and Neck Medical Oncology, randomized 41 patients with oral premalignant lesions to receive one of three concentrations of a green tea extract or a placebo three times daily for 12 weeks. Biopsies were conducted prior to and at the end of the treatment period.
Among participants who received the two highest concentrations of green tea extract, 58.8 percent showed partial clinical responses, defined as improvement in degree of maturation of epithelium with no new lesions or progression, while complete or partial responses were observed in 36.4 percent of those who received the lowest extract dose and 18.2 percent of those who received the placebo. Subjects who received green tea also tended to have improvements in biomarkers that may predict the development of cancer. Overall, green tea extract proved to be safe and well tolerated.
At the conclusion of an extended follow-up up period averaging 27.5 months, 15 participants had developed oral cancer. Although no overall difference was observed between the incidence of oral cancer in those who received green tea extract and those who didn’t, a longer time to the development of oral cancer occurred among those in the green tea groups who had mild to moderate dysplasia.
The trial is the first to test the effects of green tea as a cancer preventive among those with oral premalignant lesions. “The goal of this kind of research is to determine whether or not these supplements have long-term prevention effects.” Dr Papadimitrakopoulou remarked. “More research including studies in which individuals at high risk are exposed to these supplements for a longer time period is still needed to answer that sort of question.”
“Collecting oral tissue biopsies was essential in that it allowed us to learn that not only did the green tea extract appear to have a benefit for some patients, but we pointed to antiangiogenic effects as a potential mechanism of action,” first author Anne Tsao, MD observed. “While preliminary because our patient population was so small, this gives us direction for further study.”
“The extract’s lack of toxicity is attractive,” Dr Papadimitrakopoulou added. “In prevention trials, it’s very important to remember that these are otherwise healthy individuals and we need to ensure that agents studied produce no harm.”