Green Tea Extract in Treating Patients With Low-Risk Prostate Cancer

This randomized phase II trial studies how well green tea extract works in treating patients with low-risk prostate cancer. Green tea extract contains ingredients that may prevent or slow the growth of certain cancers.

PRIMARY OBJECTIVES: I. To assess changes in the levels of total- and free- prostate-specific antigen (PSA), free to total PSA (f/tPSA) ratio and insulin-like growth factor 1 (IGF-I) levels and IGF-I/free PSA (fPSA) ratio, insulin-like growth factor binding protein 3 (IGFBP-3), and vascular endothelial growth factor (VEGF) after Sunphenon 90DCF-T (green tea extract) supplementation during the period between recruitment and biopsy. SECONDARY OBJECTIVES: I. To evaluate the effects of oral ingestion on Sunphenon 90DCF-T supplementation during the period between recruitment and biopsy in the reactivation of glutathione S-transferase pi 1 (GSTP1) (whole blood deoxyribonucleic acid \[DNA\]); levels of antigen identified by monoclonal antibody Ki-67 (Ki-67), cluster of differentiation 34 (CD34), and M30 apopotosense in the prostate tissue. II. To evaluate the effects of oral ingestion of Sunphenon 90DCF-T during the period between recruitment and biopsy on histologic findings in prostate tissue such as nuclear measurements viz. shape, size and texture and quality of life (QOL) assessment. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM A: Patients undergo active surveillance for 52 weeks. ARM B: Patients receive green tea extract orally (PO) once daily (QD) for 52 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 30 days.