• In a population of patients designated as clinically indolent by NCCN guidelines, we will evaluate the ability of eMRI/MRSI to predict pathologically indolent cancer. eMRI/MRSI findings will be compared with step-section pathology. [ Time Frame: October 2010 ] [ Designated as safety issue: No ]
  

• In the patients who are identified as harboring indolent prostate cancer by both clinical guidelines and eMRI/MRSI, clinical progression of disease will be evaluated in a cohort of patients receiving deferred therapy. [ Time Frame: October 2010 ] [ Designated as safety issue: No ]
  

In this study, patients identified in the clinic as likely to have low-risk, organ-confined prostate cancer 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 (at 6, 18 and 36 months) TRUS-guided prostate biopsy 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.