Under the treatment schedule, 40Gy in 5 fractions is delivered to the prostate Clinical Target Volume (CTV) with an added boost to the DIL up to a total maximum of 45Gy in 5 fractions. This is limited by the dose to the urethral planning risk volume (PRV) and other nearby organs at risk.

• Aged 18 years or older
• WHO performance score 0-2 or Karnofsky performance status 70-100%
• Biopsy-proven adenocarcinoma of the prostate
• ISUP Grade Group ≥3 (including Gleason 4+3=7, 4+4=8, 4+5=9, 5+4=9, 5+5=10)
• DIL visible on MRI and/or PSMA PET scan
• Prostate volume ≤ 90 cc on transrectal ultrasound (TRUS)
• International Prostate Symptoms Score (IPSS) ≤19
• T-stage: T2-T3b (on MRI and/or endorectal ultrasound)
• Posterior lesions will require a rectal spacer as determined by USAT. If the DIL is breaching the capsule posteriorly or involves the seminal vesicles, treatment will be precluded as a rectal spacer will be contra-indicated
• No evidence of lymph node or distant metastases on radiological staging. Staging will require mpMRI and PSMA PET scan unless there is a specific contraindication to either of these modalities
• All patients should be able to undergo MRI scans
• Reviewed by Urology SABR Advisory Team (USAT) to confirm external beam radiotherapy is an option for treatment
• Previous TURP is allowed provided there is at least eight weeks interval with radiotherapy
• The administration of concomitant hormonal therapy is allowed

• Previous irradiation in the pelvic region
• Previous prostatectomy
• Previous focal therapy to the prostate (HIFU or Cryotherapy)
• T4 disease
• Previous HoLEP or TURP in previous 6 months
• Patient without a visible area of disease on mpMRI or PSMA PET
• Patients where pelvic nodal irradiation is deemed necessary by the treating clinician
• Contraindications for MRI
• Patients who have electronic devices such as pacemakers or implanted defibrillators, deep brain stimulators, cochlear implants
• Patients who have a metallic foreign body in their eye
• Patients who have an aneurysm clip in their brain
• Patients with severe claustrophobia may not be able to tolerate an MRI scan
• Patients with inflammatory bowel disease

For all referrals, clinicians should provide:

• Prostate radiotherapy consent form
• MR linac supplementary consent form
• Booking form (electronic/paper)
• Referral letter (referring the patient to the clinical oncologist)
• Histology report
• Prostate MRI report and images if possible
• GenesisCare MRIdian assessment pro forma
• Please note some insurers may ask for a medical report.

Clinicians with credentials for SABR treatment for prostate on MRIdian can refer directly using the same process as for routine prostate patients. All cases will be reviewed by the Urology SABR Advisory Team (USAT). Radiotherapy plans will be peer reviewed.

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