OBJECTIVES:~Primary~To determine whether there is a decrease in the extent of prostate cancer as measured by endorectal MRI and magnetic resonance spectroscopy imaging in patients with symptomatic benign prostatic hypertrophy and low-risk prostate cancer treated with dutasteride for 6 months.~Secondary~To monitor the effects of dutasteride on serum testosterone, dihydrotestosterone, and free and total prostate-specific antigen (PSA).~To monitor the effects of dutasteride on symptom and quality-of-life indices.~OUTLINE: Patients receive oral dutasteride once daily for 6 months.~Patients undergo endorectal MRI and magnetic resonance spectroscopy imaging at baseline and at 1, 3, and 6 months.~Patients complete quality-of-life questionnaires using the International Index of Erectile Function Questionnaire, American Urological Association Symptom Index, Functional Alterations due to Changes in Elimination, and Spitzer Quality-of-Life Index at baseline and at 1, 3, and 6 months.
RATIONALE: Diagnostic procedures, such as MRI and magnetic resonance spectroscopy imaging, may help in learning how well dutasteride works in patients with benign prostatic hypertrophy and low-risk prostate cancer.~PURPOSE: This clinical trial is studying MRI and magnetic resonance spectroscopy imaging in patients receiving dutasteride for benign prostatic hypertrophy and low-risk prostate cancer.