2 Ablative RadioTherapy Treatments for Prostate Cancer
2 Ablative RadioTherapy Treatments for Prostate Cancer
Favorable-risk prostate cancer represent a large proportion of patients diagnosed with
 prostate cancer and image guided radiation therapy (IGRT) is commonly used to treat these
 patients using protracted courses of up to 39 treatments over 8 weeks. Stereotactic ablative
 body radiotherapy (SABR) protocols hold the promise of more convenience, less side effects,
 less cost and improved system capacity without sacrificing excellent cancer control rates. By
 the same token, prostate high-dose rate (HDR) brachytherapy boost has been shown to be
 superior to standard external beam radiation. While two HDR fractions appear to optimize
 patient convenience and outcomes while minimizing costs, we wanted to determine the
 tolerability of combining one MR-guided HDR treatment with one SABR treatment to further
 reduce HDR resource use while maintaining favourable treatment outcomes.
Pre-Treatment:

 Planning CT and mpMRI imaging for SABR TRUS with biopsy and insertion of Gold Seed Fiducial
 Markers Biobanking of urine, blood and biopsy tissue (as per REB#079-2006 Odette Cancer
 Centre (OCC) biobanking protocol)

 Stereotactic Ablative Body Radiation (SABR):

 13.5Gy x 1 to whole prostate + 1cm seminal vesicles 2 weeks post-planning, treatment will be
 delivered as per standard treatment protocols on SABR-compatible linear accelerator with a
 six-degree of freedom couch. Cone-beam CT imaging will be performed using the implanted
 fiducials to set up each treatment. All dosimetric parameters will be recorded.

 Inter-treatment (approx 1 week post-SABR):

 Planning mpMRI and TRUS imaging for HDR Biobanking of urine and blood (as per REB#079-2006
 OCC biobanking protocol)

 HDR brachytherapy:

 13.5 Gy x 1 to the prostate, <20 Gy to DIL Approx 2-3 weeks post-SABR, the HDR dose
 prescription of 13.5 Gy to the whole gland and <20 Gy to MRI visible lesion will be delivered
 in one fraction, assuming that dose constraints to critical organs can be met. All dosimetric
 parameters will be recorded

 Patient Assessments / Follow-up Time zero will be the date of SABR treatment. Baseline
 rectal, urinary and sexual function will be recorded prior to treatment. Acute toxicities
 will be assessed at 6, 12 and 24 weeks and late toxicities will be assessed at month 9, 24
 and every 6 months until year 5 using the Common Terminology Criteria Adverse Events, V 4.0.
 Bloodwork (PSA and testosterone) and International Prostate Symptom Score (IPSS) evaluations
 will be performed at baseline week 6, month 3, 6, 9 and 24, and every 6 months until year 5.
 QOL using the Expanded Prostate Cancer Index Composite (EPIC), EQ-5D and PORPUS
 questionnaires will be obtained at baseline, month 3, 6, 9 and 24 and every 6 months until
 year 5. Post-treatment biobanking will be done at 13 and 52 weeks (as per REB#079-2006 OCC
 biobanking protocol)
Inclusion Criteria:

 -  Histologically confirmed diagnosis of adenocarcinoma of the prostate

 -  Favorable risk disease defined as either:

 -  Low risk disease: T1-T2c, grade group 1, PSA < 10 ng/ml or

 -  Favorable intermediate risk disease: One of T2c, grade group 2, or PSA 10-20
 ng/ml. Patients cannot have percent core positivity > 50%

 -  Prostate volume < 60 cc as determined by US, CT or MRI

 -  Ability to undergo MR imaging

 -  Provide written informed consent

 Exclusion Criteria:

 -  Documented nodal or distant metastases

 -  Previous pelvic radiotherapy

 -  Previous transurethral resection of prostate, previous prostatectomy or HIFU

 -  Use of androgen deprivation therapy. Use of 5-alpha-reductase inhibitors permitted

 -  Poor baseline urinary function defined as International Prostate Symptom Score (IPSS)
 >15

 -  Contra-indication to radical prostate radiotherapy e.g. connective tissue disease or
 inflammatory bowel disease

 -  Significant medical co-morbidity rendering patient unsuitable for general anaesthesia