Can Green Tea Prevent Cancer?

Scientists aren’t quite ready to come right out and anoint green tea as a method of cancer prevention, but evidence continues to mount about the brew’s ability to protect against the Big C. Now, a new study has been published in the American Association for Cancer Research’s journal Cancer Prevention Research which says that green tea may fight oral cancer.

Study author Vassiliki Papadimitrakopoulo, M.D., a professor of medicine in the University of Texas’s M.D. Anderson Cancer Center’s Department of Thoracic/Head and Neck Medical Oncology along with his team, gave patients an oral green tea extract. The extract was given in three separate doses and distributed to 41 patients in doses of 1,000 mg/m2, 750 mg/m2, or 500 mg/m2.

Improved Histology

The team then noted the clinical responses of the patients to each dose on their pre-malignant oral lesions, and discovered that of those patients treated with the highest dose, 58.8% responded to the extract in comparison with only 18.2% of those taking a placebo. There was an improvement in histology and in certain biomarkers that tend to be good predictors for how the cancer will develop.

The patients were watched for 27.5 months and by the end of the study, 15 of them were found to have developed oral malignancies. While there was no difference between the groups in terms of the number of those who developed oral cancer, those patients who had presented with mild or moderate dysplasia developed their cancer at a slower rate if they had been treated with the green tea extract.

Encouraging Results 

While Papadimitrakopoulo is encouraged by these results, he cautions against claims for green tea as a preventative against cancer. “This is a phase II study with a very limited number of patients who took what would be the equivalent of drinking eight to 10 cups of green tea every single day,” said Papadimitrakopoulo. “We cannot with certainty claim prevention benefits from a trial this size.”

Other experts agree with this assessment but nonetheless feel that the study gives a direction to further research on the subject. Professor of hematology and medical oncology and the Blomeyer Endowed Chair in Cancer Research at the Emory School of Medicine, Dong Shin, M.D., said, “A clinical trial with a natural compound is no easy task, and these researchers have accomplished that. The lack of toxicity is also important because often when you give supplements at higher doses than what would occur naturally, you induce nausea and vomiting.”

No Side Effects

Shin, who is also an editorial board member of Cancer Prevention Research, emphasizes that no such side effects were seen in this study on green tea extracts, even at the highest doses.

Neither Shin nor Papadimitrakopoulo felt it important to stress that those concerned about cancer should not believe that the tea could act as a cancer cure or preventative.