Stereotactic Body Radiation Therapy With Boost Using Urethral-Sparing Intensity-Modulated Radiation Therapy Planning in Treating Patients With Prostate Cancer

Inclusion Criteria: * Histologically confirmed diagnosis of adenocarcinoma of the prostate and most recent biopsy within 180 days of study enrollment * History/physical examination with digital rectal examination of the prostate within 90 days prior to study enrollment * Gleason score =\< 7, no tertiary pattern \>= 5 * Clinical stage =\< T2b (American Joint Committee on Cancer \[AJCC\] 7th Edition Staging Manual) and no radiographic evidence of T3 or T4 disease * Clinical stage N0, M0 * Most recent prostate specific antigen (PSA) within 60 days of enrollment * Maximum PSA =\< 20 ng/ml (not within 20 days after biopsy) * Eastern Cooperative Oncology Group (ECOG) performance status 0-1 * American Urological Association (AUA) =\< 18 with or without medical management * Up to a total of year of androgen deprivation allowed. * Participant signs study specific informed consent prior to study enrollment Exclusion Criteria: * FOR ARM A: Inability to obtain a planning MRI or a planning MRI of sufficient quality to allow identification of the peripheral zone and urethra, or inability to adequately fuse the MRI to the planning CT scan * FOR BOTH ARM A AND ARM B: * Prior or concurrent invasive malignancy (except non-melanomatous skin cancer) or lymphomatous/hematogenous malignancy unless continually disease free for a minimum of 5 years; (for example, carcinoma in situ of the bladder or oral cavity is permissible) * Prosthetic implants in the pelvic region that the investigator feels …