Stereotactic Body Radiotherapy for Prostate Cancer

Inclusion Criteria: 1. Men aged ≥18 years 2. Histological confirmation of prostate adenocarcinoma requiring radical radiotherapy 3. Gleason score 3+4 or 4+3 (Grade groups 2 or 3) 4. MRI stage T3a or less 5. PSA \<25 ng/ml prior to starting ADT (Androgen deprivation therapy) 6. Patients will be concurrently treated with androgen deprivation therapy (ADT) for at least 6 months, as per standard of care. Men who need longer courses of ADT (maximum 12 months) will be considered on a case-by-case basis, and bicalutamide monotherapy is accepted as an alternative to LHRH (luteinizing hormone-releasing hormone) analogues if required. 7. WHO (World Health Organisation) Performance status 0-2 8. Ability of the participant understand and the willingness to sign a written informed consent form. 9. Ability/willingness to comply with the patient reported outcome questionnaires schedule throughout the study. Exclusion Criteria: 1. Contraindications to MRI (e.g. pacemaker, potentially mobile metal implant, claustrophobia) 2. International Prostate Symptom Score (IPSS) 13 or higher 3. Post-void residual \>100 mls 4. Prostate volume \>80cc 5. Comorbidities which predispose to significant toxicity (e.g. inflammatory bowel disease) or preclude long term follow up 6. Unilateral or bilateral total hip replacement, or other pelvic metalwork which causes artefact on diffusion-weighted imaging 7. Previous pelvic radiotherapy 8. Patients needing 2-3 years of ADT due to disease parameters. 9. Previous invasive malignancy within the last 2 years excluding basal or squamous cell carcinomas of the skin, low risk non-muscle invasive bladder cancer (assuming cystoscopic follow up now negative) or small renal masses on surveillance.