Dose Escalation Study of Preoperative SBRT for High Risk Prostate Cancer

Inclusion Criteria: * Histologically-proven prostate adenocarcinoma. * Clinical stage ≤T3a based on digital rectal exam and/or ≤T3a based on MRI (if done); N0-Nx; M0-Mx (AJCC 7th Edition) * Prostate-specific antigen (PSA) ≤ 80 ng/ml, obtained within 3 months. * Patients belonging in the National Comprehensive Cancer Network (NCCN) high recurrence risk group. High risk: Clinical stage T3a, or Gleason score = 8-10, or PSA \>20 ng/mL. * Prostate volume: ≤ 80 cc on transrectal ultrasound * IPSS score ≤15 * Zubrod performance status 0-2 or equivalent * No prior total prostatectomy or cryotherapy of the prostate. Prior transurethral resection or laser ablation is permitted. * No prior radiotherapy to the prostate or lower pelvis * No implanted hardware or other material that would prohibit appropriate treatment planning or treatment delivery, in the investigator's opinion * No history of an invasive malignancy (other than this prostate cancer, or non-metastatic basal or squamous skin cancers) in the last 5 years * No androgen deprivation therapy (ADT) can be prescribed prior to or during radiation therapy * Must be able to have gold fiducial markers placed in the prostate or, if patient already has fiducial markers placed, they must be in accordance with the protocol specifications * Ability to understand and the willingness to sign a written informed consent document * Willingness to fill out IPSS, SHIM, and EPIC quality of life forms * Age ≥18 years * IPSS (AUA) score ≤15 Exclusion Criteria: * Does not have a diagnosis of prostate adenocarcinoma * Has very low risk, low risk, intermediate risk or very high risk disease as defined by the NCCN * Has stage N1 or M1 (metastatic) disease * Has a PSA of greater than 80 ng/ml obtained no greater than 3 months prior to randomization * Prostate volume greater than 80 cc on transrectal ultrasound * Zubrod performance status 3 or greater * Prior total prostatectomy or cryotherapy of the prostate * Prior radiation therapy to the pelvis * Implanted hardware which limits treatment planning or delivery (determined by the investigator). * Diagnosis of an invasive malignancy within 5 years (other than current prostate cancer or non-metastatic basal or squamous skin cancers) * The use of androgen deprivation therapy (ADT) prior to registration or during radiation * Inability to have gold fiducial markers placed in the prostate, or fiducial markers already placed, that are not in accordance with the protocol * Unwilling or inability to give informed consent * Not willing to fill out IPSS, SHIM, and EPIC quality of life questionnaires * IPSS score \>15