Internal Radiation Therapy in Treating Patients With Low-Risk Prostate Cancer

PRIMARY OBJECTIVES: I. To determine long term 5 year prostate specific cancer (PSA) biochemical control using the Phoenix definition of PSA nadir + 2 of targeted hemi-gland brachytherapy. SECONDARY OBJECTIVES: I. To assess acute and late toxicity outcomes following targeted brachytherapy according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v4.0. II. To determine changes from baseline in health-related quality of life indicators using the validated Expanded Prostate Cancer Index Composite (EPIC) questionnaire, International Index of Erectile Function (IIEF) questionnaire, and International Prostate Symptom Score (IPSS) questionnaire. III. To assess the potential value of multiparametric magnetic resonance imaging, including dynamic contrast enhancement perfusion imaging and diffusion tensor neurovascular tactographic imaging in predicting the development of equivocal disease (ED) following radiation treatment. OUTLINE: Patients undergo 3 fractions of image-guided high-dose rate (HDR) brachytherapy over 2 days. After completion of study treatment, patients are followed up every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.