UP-25 Focal low dose-rate brachytherapy for low to intermediate prostate cancer: preliminary experience at an Australian institution.
Thursday June 27, 2019 from

Elliot P Anderson, Australia

Monash Universtiy


Focal low dose-rate brachytherapy for low to intermediate prostate cancer: Preliminary experience at an Australian institution

Elliot Anderson1, Lloyd Smyth2, Richard O'Sullivan3,4, Andrew Ryan5, Nathan Lawrentshuk6,7,8,9, Jeremy Grummet1,10, Andrew See2.

1Department of Surgery, Monash University, Melbourne, Australia; 2Icon Cancer Centre, Richmond, Australia; 3Healthcare Imaging Services, Richmond, Australia; 4Department of Medicine, Monash University, Melbourne, Australia; 5TissuPath Specialist Pathology Services, Mont Waverley, Australia; 6Division of Cancer Surgery, Peter MacCallum Cancer Centre, Melbourne, Australia; 7Department of Urology, Royal Melbourne Hospital, Melbourne, Australia; 8Department of Surgery, University of Melbourne, Melbourne, Australia; 9EJ Whitten Centre for Prostate Cancer Research , Epworth Healthcare, Melbourne, Australia; 10Epworth Healthcare, Melbourne, Australia

Introduction: Focal therapy for patients with low-intermediate risk features is an emerging modality aimed at reducing treatment-related toxicity. With more  accurate diagnostic imaging using MRI, focal treatment with low dose rate (LDR) brachytherapy has become a viable ablation option. Our objective was to evaluate the dosimetry, toxicity and oncological outcomes of men receiving lesion-targeted focal LDR brachytherapy for low to intermediate risk prostate cancer (PCa).

Methods: This is a retrospective study of twenty-six men with unifocal, low to intermediate grade PCa diagnosed on a combination of multiparametric (mp)-MRI and targeted plus template transperineal (TP) biopsy, who received focal LDR brachytherapy at a single institution. Brachytherapy involved a single monotherapy implant using iodine-125 seeds to deliver a prescribed dose of 145 Gy to the index lesion.

Results: The mean planning target volume as a percentage of the prostate volume was 24.5%. Good post-implant dosimetry outcomes (British Columbia Cancer Agency criteria) were achieved in 22 (84.6%) patients. The median follow-up for toxicity and biochemical control outcomes was 19.0 (IQR 12.4–30.5) and 18.1 (IQR 14.2–27.6) months, respectively. Grade 2 urinary and erectile toxicities were reported by 29.2% and 37.5% of patients, respectively, with resolution of urinary symptoms to baseline by last follow-up. There were no grade ≥3 urinary or erectile toxicities or grade ≥2 rectal toxicity. All 15 patients who underwent a repeat mp-MRI and/or TP biopsy at 12–18 months post-treatment were negative for clinically significant disease and 25 (96.2%) patients were free from biochemical failure.

Conclusion: Focal LDR brachytherapy is associated with a favourable toxicity profile and a high rate of successful ablation of significant prostate cancer. We have commenced the LIBERATE prospective registry in focal LDR brachytherapy based on the highly encouraging outcomes of this initial experience.

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