MRI-Mapped Dose-Escalated Salvage Radiotherapy Post-Prostatectomy: The MAPS Trial

1. The investigators hypothesize that increasing radiation dose to the functional MRI-defined lesion in the prostate bed will result in an improved initial complete response (reduction in prostate-specific antigen (PSA) to \< 0.1 ng/mL), which is related to long-term outcome biochemically. 2. Biomarker expression levels differ in the DCE-MRI enhancing and non-enhancing tumor regions (when applicable). 3. 10-15% of men undergoing RT have free circulating DNA (fcDNA) or tumor cells (CTC) that are related to an adverse treatment outcome. 4. Prostate cancer-related anxiety will be reduced in the MRI targeted SRT arm, because the patients will be aware that the dominant tumor will be targeted with higher radiation dose (compared to those pts who were treated on standard arm prior to its closure).