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.