5 Fractions of Pelvic SABR With Intra Prostatic SABR (5STAR)

Inclusion Criteria:

• Histologically confirmed prostate adenocarcinoma (centrally reviewed)
• High- tier intermediate risk defined as:

PSA 10-20ng/ml AND (T2b-2c OR Gleason 7 )

• High-risk prostate cancer, defined as at least one of: T3, OR Gleason 8-10, OR PSA > 20 ng/mL

• Willing to give informed consent to participate in this clinical trial
• Able and willing to complete Expanded Prostate Index Composite (EPIC) questionnaire

Exclusion Criteria:

• Prior pelvic radiotherapy
• Contra-indication to radical prostate radiotherapy e.g. connective tissue disease or inflammatory bowel disease
• Contraindication to prostate MRI
• Anticoagulation medication (if unsafe to discontinue for gold seed insertion)
• Diagnosis of bleeding diathesis
• Large prostate with significant arch interference on TRUS after 3 months of neoadjuvant ADT.
• Previous TURP
• Poor baseline urinary function defined as International Prostate Symptom Score (IPSS) >20
• Significant medical co-morbidity rendering patient unsuitable for general anesthetic
• No evidence of castrate resistance (defined as PSA < 3 ng/ml while testosterone is < 0.7nmol/l. Patients could have been on combined androgen blockade but are excluded if this was started due to PSA progression.
• Definitive extrapelvic nodal or distant metastatic disease on staging investigations.