Inclusion Criteria:  Histologically confirmed diagnosis of adenocarcinoma of the prostate status post radical prostatectomy Completed written informed consent Able and willing to complete EPIC, PORPUS, and EQ-5D questionnaires A detectable PSA ≤ 2.0 ng/ml Two consecutive rises in PSA and final PSA > 0.1 ng/ml OR three or more consecutive rises in PSA  Exclusion Criteria:  Gross residual disease (per conventional imaging, i.e. CT and/or MRI) Histological or radiological node +ve (N1) or distant metastases (M1) Prior pelvic radiotherapy Contraindications to radical pelvic radiotherapy (e.g. connective tissue disease or inflammatory bowel disease)