The purpose of this study is to see if magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) can tell which patients with prostate cancer are at a low risk for their cancer growing and spreading. Magnetic resonance methods use magnets and radio waves to take pictures of body structure (MRI) and to measure amounts of important chemicals within the body (MRSI). This study will look at the structural and chemical properties of prostates before undergoing treatment. Hopefully, doctors will be able to use this method before making treatment decisions for patients with newly diagnosed cancer of the prostate. This study will continue our work to assess the value of MRI/MRSI in addressing what is currently one of the greatest clinical challenges in the management of prostate cancer: the identification of low-risk organ-confined prostate cancer that can be managed expectantly with deferred treatment.

In this study, patients with low-risk, organ-confined prostate cancer identified in clinic or prior to their already scheduled standard of care MRI in the Department of Radiology will be approached for the study. Eligible patients will undergo a baseline eMRI/MRSI exam between 6 and 24 weeks following biopsy. Patients will undergo definitive treatment (radical prostatectomy (RP) or radiation therapy (RT)) or will be placed on deferred therapy. Predictor variables will be recorded for each patient after enrollment, before treatment and during treatment follow-up. Patient outcome-disease progression will be determined by long term clinical follow-up

Inclusion Criteria:

1. Gleason ≤6 (grade 3 + 3 or lower) biopsy proven prostate cancer
2. Clinically low-risk localized disease as defined by NCCN guidelines (clinical stage T1-T2a, maximum Gleason score 2-6, peak serum PSA level < 10 ng/ml)
3. No evidence of disseminated disease (bone or lymph node metastases)
4. Treatment-radical prostatectomy, radiation therapy, or deferred therapy-will be at MSKCC
5. Willingness to undergo serial surveillance TRUS-guided prostate biopsies and eMRI/MRSI examination at MSKCC if placed on deferred therapy protocol
6. In the surgical cohort, RP (radical prostatectomy) is scheduled to occur within six months of eMRI/MRSI study

Exclusion Criteria:

1. Prior treatment (e.g. with hormonal therapy, radical prostatectomy, radiation therapy or cryosurgery)
2. Inability to give informed consent because of age, general medical or psychiatric condition, or physiologic status
3. Presence of known contraindication to eMRI
4. Unwillingness or inability to undergo placement of endorectal MR coil or ultrasound probe. As is the case for a standard MR exam, the presence of a pacemaker or aneurysm clips could pose a risk to patients, making them unable to have an eMRI, and therefore unable to participate in this study.