July, 2005, Vol. 06, Issue 07
"Numerous earlier studies, including ours, have demonstrated that green tea catechins, or pure EGCG ( epigallocatechin gallate), inhibited cancer cell growth in laboratory models," explained Dr.
Bettuzzi in an interview at the AACR meeting. "We wanted to conduct a clinical trial to find out whether catechins could prevent cancer in men. The answer clearly is, yes."3
The study involved 62 men ages 45 to 75, all of whom had been diagnosed with high-grade prostatic intraepithelial neoplasia, a type of lesion that often develops into prostate cancer within one year. Men who were vegetarians, who already consumed green tea, or who were taking antioxidant supplements or hormone therapy, were excluded from the study group.
The men were divided into two groups. A treatment group of 32 men consumed a pill containing 200 milligrams of GTCs three times per day for one year. The remaining men were given a placebo. Biopsies of the men were administered six months after the study began, and again at one year, to determine whether the lesions had metastasized into cancer.
According to the scientists, "After a follow-up period of one year, only one prostate cancer was diagnosed among the 32 men that received a daily treatment of three tablets ... of GTCs, with an incidence of 3 percent, while nine cancers were found among the 30 men treated with placebo, accounting for an incidence of 30 percent." No adverse events or side-effects associated with the GTC supplements was noted.
"To our knowledge, this is the first study showing that GTCs are safe and have a potent in vivo chemoprevention activity for human prostate cancer," the authors wrote. "Thus, administration of GTCs could be an effective therapy for treating pre-malignant lesions that takes advantage of an important window of opportunity for treatment before prostate cancer develops." They added that they will continue monitoring the patients in the trial for up to five years, but that larger studies are needed to confirm their results.