To Evaluate if Green Tea Can be Effective in Reducing the Progression of Prostate Cancer in Men on Close Monitoring

Inclusion Criteria: * INCLUSION CRITERIA FOR PREREGISTRATION (STEP 0: SCREENING) * Patient must have biopsy-proven (consisting of \>= 12 tissue cores) adenocarcinoma of the prostate with cancer present in at least one biopsy core in the most recent biopsy using initial transrectal ultrasound (TRUS) biopsy or TRUS biopsy followed by multiparametric magnetic resonance imaging (mpMRI) of the prostate and a confirmatory targeted biopsy * Patient must be on active surveillance (very low, low and favorable intermediate risk as defined by the National Comprehensive Cancer Network \[NCCN\]) * Patient must be scheduled for a follow up prostate biopsy 6 months after the initiation of treatment on this study * Patient must have a serum PSA \< 10 ng/mL or prostate specific antigen density (PSAD) \< 0.15 ng/mL/ g obtained within 30 days of registration * Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status 0-1 * Patient must be willing to abstain from consumption of any supplements containing green tea catechins * Patient must be willing to restrict tea consumption to less than three (3) servings of hot tea or three (3) servings of iced tea per week (serving size of 8 oz) * Patient must be willing to discontinue current vitamin/mineral supplement use and use one provided by study * Patient must be willing to take study agent or placebo at the dose specified with meals * Patient must have the ability to understand and the willingness to sign a written informed…