James A. Cardelli of the Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center-Shreveport, and colleagues conducted an open-label, single-arm, phase II clinical trial to determine the effects of short-term supplementation with green tea's active compounds on serum biomarkers in patients with prostate cancer.
The biomarkers include hepatocyte growth factor, vascular endothelial growth factor and prostate specific antigen. HGF and VEGF are good prognostic indicators of metastatic disease, Cardelli said.
The study included 26 men, ages 41-72 years, diagnosed with prostate cancer and scheduled for radical prostatectomy -- removal of the prostate. Patients consumed four capsules containing Polyphenon E until the day before surgery -- four capsules are equivalent to about 12 cups of normally brewed concentrated green tea, Cardelli said.
The time of study for 25 of the 26 patients ranged from 12 days to 73 days, with a median time of 34.5 days.
"Unfortunately, this trial was not a randomized trial, which would have been needed to be more sure that the observed changes were truly attributable to the green tea components and not to some other lifestyle change -- better diet, taking vitamins, etc. -- men undertook in preparation for surgery," Dr. William G. Nelson of The Johns Hopkins Kimmel Cancer Center and senior editor for Cancer Prevention Research said in a statement.