A leading cancer center reports that green tea extract may be helpful in preventing oral cancer in patients who have a pre-malignant condition called oral leukoplakia. The five-year survival rate among oral cancer patients is less than 50 percent.
Green tea extract has been the focus of many studies, with research suggesting that the natural supplement is beneficial in preventing bone loss, protecting the lungs of smokers, slowing progression of prostate cancer, and reducing the risk of dying of colon cancer or heart disease.
Approximately 35,000 people were diagnosed with oral cancer in 2008. The rate of occurrence is increasing, according to the Oral Cancer Foundation, with an increase of more than 11 percent between 2007 and 2008. A person dies of oral cancer at the rate of every hour of every day. The two main risk factors for oral cancer are use of tobacco and alcohol, and exposure to the HPV-16 virus (human papilloma virus version 16), which causes cervical cancer.
The University of Texas M.D. Anderson Cancer Center study was the first to investigate green tea as an agent to protect against cancer in this high-risk population of patients with oral leukoplakia. The Phase II study involved 41 patients who were randomly assigned to received either green tea extract or placebo. The patients who took the green tea for three months received one of three doses: 500 per meter squared of body mass (mg/m2); 750 mg/m2, or 1,000 mg/m2, three times daily.
The investigators collected oral tissue samples at baseline and after 12 weeks of treatment to determine whether the green tea extract was having an impact. The samples revealed that the green tea was beneficial for patients and that it has an anti-angiogenic effect. This means that green tea helps stop the production of new blood vessels in a tumor, which promotes its growth. Thus green tea extract appears to have an anti-cancer effect.
Patients who took the green tea extract benefited at all doses. At the two highest doses, 58.8 percent had a clinical response, compared with 36.4 percent in the lowest dose and 18.2 percent among the placebo group. At a follow-up with a mean of 27.5 months, 15 participants had developed oral cancer, with a median time to the development of disease of 46.4 months.
Along with showing promise as an oral cancer preventive, the green tea extract used in the study was also well tolerated. Side effects included insomnia and nervousness, which were experienced mostly in the highest dose group. The study’s authors noted that the green tea extract they used was developed exclusively as a pharmaceutical and was not available over-the-counter.