The study included 26 men, 41 to 72 years old, who had prostate cancer and were scheduled for radical prostatectomy. The men took four capsules a day of an investigational agent called Polyphenon E, an amount equivalent to about 12 cups of normally brewed, concentrated green tea. The men took the capsules for 12 to 73 days, with a median time of 34.5 days, but stopped the day before surgery.
The phase 2 study found "significant" reductions in the men's serum levels of markers predictive of prostate cancer progression, including hepatocyte growth factor, vascular endothelial growth factor and prostate specific antigen. In some men, reductions in levels of these markers were greater than 30 percent, the researchers found.
There were few reported side effects, and the men's liver function remained normal, according to James A. Cardelli, a professor and director of basic and translational research at the Feist-Weiller Cancer Center at Louisiana State University Health Sciences Center-Shreveport, and his research colleagues. The findings are reported in Cancer Prevention Research.
A recent year-long clinical trial in Italy found that consumption of reduced prostate cancer risk in men with high-grade prostate , according to a news release from the American Association for Cancer Research.
"These studies are just the beginning, and a lot of work remains to be done," Cardelli said in the news release. "However, we think that the use of tea polyphenols alone or in combination with other compounds currently used for cancer therapy should be explored as an approach to prevent cancer progression and recurrence."