Radiation Hypofractionation Via Extended Versus Accelerated Therapy (HEAT) For Prostate Cancer

Accelerated Hypofractionation Radiotherapy for prostate cancer of 36.25 Gy delivered in 5 fractions will not be inferior to the standard treatment of 70.2 Gy given in 26 fractions with respect to four-year biochemical failure (PSA failure) by Phoenix definition post-treatment completion.

Inclusion Criteria: 1. Histologically proven prostate adenocarcinoma. * Gleason score 2-7 (reviewed by reference lab at UM). * Biopsy within one year of date of enrollment. 2. Clinical stage ≤ T2 based on DRE and/or ≤ T3a based on MRI (if done); N0-Nx; M0-Mx (AJCC 7th Edition) * T-stage and N-stage determined by physical exam and available imaging studies (CT, and/or MRI of the pelvis; see section 4.5). For MRI, questionable extracapsular extension is permitted. To distinguish blood from tumor the ideal study would be to acquire T2, T1 noncontrast and T1 dynamic contrast enhanced sequence, although this is not required. A small amount of extracapsular extension is permitted, as long as it can be included in the clinical target volume (CTV) and the constraints are met. * M-stage determined by physical exam, CT or MRI. Bone scan not required unless clinical findings suggest possible osseous metastases. 3. Prostate-Specific Antigen (PSA) \< 20 ng/ml, obtained no greater than 3 months prior to enrollment. 4. Patients belonging in one of the following risk groups: * Low: * Clinical stage\* T1-T2; Gleason ≤ 6, PSA ≤ 10 \& \