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.