This phase I study will assess the toxicity profile and efficacy of SBRT (Stereotactic body radiotherapy) in patients with localized prostate cancer who are considered candidates for post-prostatectomy radiation.

Radical prostatectomy is a common treatment for localized prostate cancer, patients with a detectable and/or rising PSA after radical prostatectomy may be offered radiation. An increasing number of patients are being referred post-operatively for radiotherapy, which creates an added burden on radiotherapy departments. Therefore, a strategy that could potentially decrease the number of radiotherapy fractions, yet maintain its efficacy, would be highly desirable for patient convenience, cost saving, and resource utilization as long as the toxicity profile is acceptable. This study will be conducted to asses the toxicity and efficacy of Stereotactic body radiotherapy (SBRT) in post-prostatectomy patients.

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)