MRI and Magnetic Resonance Spectroscopy Imaging in Patients Receiving Dutasteride for Benign Prostatic Hypertrophy and Low-Risk Prostate Cancer

Inclusion criteria: * Histologically confirmed adenocarcinoma of the prostate * Clinical stage T1b, T1c, or T2a disease * Gleason score ≤ 6 * Maximal prostate-specific antigen (PSA) \< 10 ng/mL * Demonstrates intra-prostatic metabolite abnormalities, consistent with adenocarcinoma of the prostate (i.e., ≥ 3 voxels with magnetic resonance spectroscopy imaging \[MRSI\] scores 4-5) by baseline MRI and MRSI * Has symptomatic benign prostatic hypertrophy and is currently undergoing watchful waiting OR opting to undergo permanent seed implant (i.e., brachytherapy), but requires neoadjuvant androgen suppression for prostate shrinkage * No regional lymph node involvement * No evidence of distant metastases * Zubrod performance status 0-1 * Able to swallow and retain oral medications Exclusion Criteria: * Other prior or concurrent invasive cancer, other than localized basal cell or squamous cell carcinoma of the skin * Contraindications to MRI/MRSI, including any of the following: * Prostate biopsy (within the past 8 weeks) and any continued post-biopsy bleeding * Rectal bleeding * Anal fissures * Rectal surgery (end-to-end anastomosis) * Inflammatory bowel disease * Prior radical prostatectomy * Hip replacement * Certain types of penile implants * Vascular clips * Known anaphylactic reaction to latex compounds * Anticoagulant drugs * Severe claustrophobia * Cardiac pacemaker * Metal in eye * Any other metallic or foreign object in the body * Unstable serious co-morbidities including, but not limited to, myocardial infarction, coronary artery syndrome, cardiac arrhythmias, symptomatic congestive heart failure, or cerebrovascular accident * Major medical or psychiatric illness that, in the investigator's opinion, would preclude the completion of treatment and interfere with follow up * Known hypersensitivity to any 5α-reductase inhibitor or drug chemically related to the study drug * Prior radical surgery (prostatectomy) or cryosurgery for prostate cancer * Prior pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy * Prior or concurrent cytotoxic chemotherapy for prostate cancer * Prior hormonal therapy, such as luteinizing hormone-releasing hormone agonists (e.g., goserelin or leuprolide acetate), antiandrogens (e.g., flutamide or bicalutamide), or estrogens (e.g., diethylstilbestrol) * Prior or concurrent finasteride, dutasteride, other drugs with known antiandrogenic properties (e.g., spironolactone or progestational agents), or any dietary or herbal supplement (e.g., selenium, vitamin E, saw palmetto, or PC-SPES)