Stereotactic Body Radiation Therapy in Treating Patients With Localized Prostate Cancer That Have Undergone Surgery

Inclusion Criteria:

* History of histologically confirmed, clinical localized adenocarcinoma of the prostate treated with radical prostatectomy with definitive intent
* Presence of adverse pathologic features at the time of prostatectomy (positive surgical margin, pathologic T-stage 3-4 disease, pathologic Gleason score 8-10 disease, presence of tertiary Gleason grade 5 disease) OR documentation of rising prostate-specific antigen on at least two consecutive draws, with the magnitude of prostate-specific antigen exceeding 0.03 ng/mL
* Computed tomography (CT) scan and MRI of the pelvis within 120 days prior to enrollment (note: \[a\] if patient has medical contraindication to MRI, an exemption will be granted and enrollment can proceed \[b\] for patients with PSA \< 1.0 ng/mL, the treatment planning CT can substitute for a diagnostic CT scan)
* Bone scan within 120 days prior to enrollment; if the bone scan is suspicious, a plain x-ray and/or MRI must be obtained to rule out metastasis, and advanced imaging (e.g., 18NaF positron emission tomography \[PET\]/CT) is strongly recommended
* Karnofsky performance score (KPS) \>= 70
* Ability to understand, and willingness to sign, the written informed consent

Exclusion Criteria:

* Patients with any evidence of distant metastases
* Patients with pathologically-confirmed N1 prostate cancer
* Patients with neuroendocrine or small cell carcinoma of the prostate
* Prior cryosurgery, high-intensity focused ultrasound ablation (HIFU) or brachytherapy of the prostate
* Prior pelvic radiotherapy
* History of Crohn's disease, ulcerative colitis, or ataxia telangiectasia