Partial Prostate Salvage High Dose Rate Brachytherapy
Partial Prostate Salvage High Dose Rate Brachytherapy
A dose-response relationship for radiation in the management of prostate cancer is well
 established. Local recurrence of prostate cancer after external beam radiotherapy occurs in
 at least 40% of patients treated because of inability to deliver sufficient dose through
 external beam techniques. These patients respond well to re-irradiation using brachytherapy
 with about 50% of selected patients remaining free of recurrence 5 years after salvage.
 Advanced imaging using multiparametric Magnetic Resonance Imaging (mpMRI) allows
 identification of the site of recurrence, permitting partial prostate salvage brachytherapy.
 There is extensive literature on Low Dose Rate salvage brachytherapy but less on High Dose
 Rate.
Appropriately selected patients with histologically documented recurrence 3 years or more
 after initial external beam radiotherapy will undergo mpMRI for identification of the site of
 recurrence. A planning transrectal ultrasound (TRUS) will be obtained for fusion with the
 mpMRI and transposition of the target volume (GTV=gross tumor volume). A margin of 4.5 cm
 will be added to the GTV to create a focal planning target volume (PTV). The margin may be
 cropped at the interface with critical organs. Two fractions of HDR brachytherapy will be
 delivered, each from a single implant, 2 weeks apart. Following treatment patients will be
 monitored for toxicity and quality of life using the Expanded Prostate cancer Index (EPIC)
 questionnaire as well as the International Prostate Symptom score. Efficacy will be evaluated
 by monitoring the Prostate Specific Antigen (PSA) and repeat mpMRI at 2 years.
Inclusion Criteria:

 -  Age >45 and Life expectancy >10 years

 -  Previous External Beam Radiotherapy (EBRT) dose up to 78Gray/39 fractions, 81 Gray/45
 fractions or 70 Gray/28 fractions

 -  > 3 year interval since EBRT

 -  No late toxicity from prior EBRT > grade 2

 -  Rising PSA post EBRT > nadir + 2 ng/ml but < 10 ng/ml

 -  PSA Doubling time > 6 months

 -  Negative staging with CT scan of the abdomen/pelvis and bone scan

 -  Able to undergo multiparametric MRI with endorectal coil

 -  Radiographic evidence of dominant intraprostatic lesion (DIL) as only area of
 recurrence (i.e unifocal recurrence) and corresponding to site of original disease

 -  Biopsy confirmation of DIL with pathology review by British Columbia Cancer Agency
 GenitoUrinary pathologist (TB)

 -  Willing to provide informed consent

 -  History and physical examination within 90 days of registration

 -  ECOG performance status 0-1 prior to registration

 -  IPSS < 16, or adequate voiding study (post void residual < 100cc and peak flow rate >
 10 cc/second).

 -  No prior trans urethral prostatic resection

 -  Recurrence suitable for implant with HDR brachytherapy as assessed on ultrasound
 simulation (maximum PTV ideally < 65% of prostate volume)

 -  No history of inflammatory bowel disease or previous rectal surgery

 -  Suitable for procedure under anesthesia, spinal or general

 -  INR <2.5 and platelet count >75 x 109/L

 -  Androgen Deprivation Therapy may be initiated at the discretion of the treating
 oncologist

 Exclusion Criteria:

 -  Not compliant with criteria above

 -  Unable to give informed consent