Metformin Hydrochloride in Treating Patients With Prostate Cancer Undergoing Surgery

PRIMARY OBJECTIVES: I. To determine the effect of 4-12 weeks of metformin (metformin hydrochloride) intervention on cell proliferation in the prostatectomy tissue. SECONDARY OBJECTIVES: I. To determine the effect of metformin intervention on prostate tissue bioavailability of metformin. II. To determine the effect of metformin intervention on apoptosis and angiogenesis in the prostatectomy tissue. III. To determine the effect of metformin intervention on potential molecular targets of metformin including activated protein kinase (AMPK) activation, mammalian target of rapamycin (mTOR) regulation, and cell cycle regulation in the prostatectomy tissue. IV. To determine the effect of metformin intervention on changes in systemic hormones and growth factors that have been shown to be modulated by metformin in other patient populations including fasting glucose, fasting insulin, insulin-like growth factor axis, testosterone, and sex hormone binding globulin (SHBG). V. To determine the effect of metformin intervention on changes in prostate-specific antigen (PSA) levels. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive extended-release metformin hydrochloride orally (PO) once daily (QD) for 4-12 weeks. ARM II: Patients receive placebo PO QD for 4-12 weeks. Patients in both arms undergo surgery one day after completion of treatment. After completion of study treatment, patients are followed up within 30 days of surgery.