High-Dose-Rate Brachytherapy

This pilot study initiates a research program testing the early technical and clinical performance of a novel procedure for MRI-guided high-dose-rate (HDR) prostate brachytherapy. Testing will proceed in two cohorts of patients. In Arm 1, patients with locally recurrent prostate cancer after radiotherapy will receive tumor-targeted salvage HDR brachytherapy. Arm 1 of the study will be coordinated and closely integrated with a separate concurrent study of MRI-guided prostate biopsy, which will be performed prior to accrual to Arm 1 of this trial (UHN 05-0641-C). In arm 2, patients with locally advanced prostate cancer will receive a boost of prostate-targeted HDR brachytherapy during external beam radiotherapy. This technique will be prospectively evaluated in up to 100 patients. Preliminary data acquired in this pilot study will determine the technical limits of MRI guided HDR brachytherapy and will be critical for the judicious conduct of a subsequent phase II clinical trial. This proposal is innovative in two fundamental ways: MRI-guidance, and specific tumor targeting for HDR brachytherapy. Successful completion of this study will further individualize local therapy, not only for the benefit of the proportion of cancer patients for whom initial radiotherapeutic interventions have failed, but also provide valuable technical and clinical validation that these novel image-guided (IG) approaches are clinically feasible and could be applied more broadly in prostate cancer therapy.