Green Tea and Cancer Prevention: New Clues
Green Tea & Breast Cancer
Other researchers reported that an extract from green tea, Polyphenon E, may help inhibit breast cancer by affecting substances called growth factors. Growth factors are involved in the signals that tell breast cancer to grow.
In earlier research, Katherine Crew, MD, assistant professor of medicine and epidemiology at Columbia University Medical Center in New York, had assigned 40 women already treated for breast cancer to take 400, 600, or 800 milligrams of the extract or to take a placebo twice daily for six months.
That was a study to examine any toxic effects of the extract. For the current study, she evaluated blood and urine samples from 34 of the women to see how the extract might work as a cancer fighter.
"We wanted to better understand the biological effects," she says.
"After two months of Polyphenon E, there was a reduction in hepatocyte growth factor," she says. This is one of the growth factors that affect breast cancer cell growth, spread, and invasion. That reduction declined and was not different from the placebo group at four months, however.
It's still too early to recommend green tea extract as a way to prevent breast cancer, Crew says.
Green Tea & Breast Cancer: Perspective
The new research on green tea and breast cancer adds to growing evidence of its benefits, according to Joanne Mortimer, MD, director of the Women's Cancer Program at the City of Hope Comprehensive Cancer Center.
"There really does seem to be something there," she says. The new study provides a potential explanation for why green tea may help, she says.
So should women drink green tea with an eye to prevention of breast cancer?
"I don't think we are quite ready to make that leap," Mortimer says. "But it is pretty interesting."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.