The purpose of this study was to determine whether the daily consumption of decaffeinated green tea catechins (Polyphenon E®) for 1 year reduces the rate of progression to prostate cancer (PCa) in men diagnosed with HGPIN or ASAP. The aim was to recruit and treat 240 (120 men/arm) men diagnosed with the prostate condition HGPIN or ASAP with a capsule form of standardized green tea extract called Polyphenon E or placebo for a 12-month period and see if it can prevent progression of the prostate condition to prostate cancer. Investigators wanted to see if Polyphenon E reduces lower urinary tract symptoms and if this can be taken safely over one year. Investigators wanted to study how Polyphenon E is able to slow the progression to prostate cancer, or the mechanism of action of Polyphenon E. If the safety and the effects of Polyphenon E on slowing down the progression of prostate cancer is shown in our study, this will be a safe way of treating men who are at high risk or men like you who have a prostate condition that increases your chances of getting prostate cancer, so that we can prevent prostate cancer in the future.