Clinical Investigation Patterns of Recurrence After Low-Dose-Rate Prostate Brachytherapy: A Population-Based Study of 2223 Consecutive Low- and Intermediate-Risk Patients Andrea C. Lo, MD, W. James Morris, MD, FRCPC, Tom Pickles, MD, FRCPC, Mira Keyes, MD, FRCPC, Michael McKenzie, MD, FRCPC, and Scott Tyldesley, MD, FRCPC Department of Radiation Oncology, British Columbia Cancer Agency Vancouver Centre, and Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada Received Oct 31, 2014, and in revised form Dec 4, 2014. Accepted for publication Dec 5, 2014. Summary We reported patterns of recurrence in a large cohort of patients treated with prostate lowedose-rate brachytherapy (LDR-PB), estimated local recurrence rate, and compared that rate to the estimated local recur- rence rate after radical pros- tatectomy (RP) in the same population. This population- based analysis suggests that Objectives: This study examined patterns of recurrence after lowedose-rate prostate brachytherapy (LDR-PB), estimated local recurrence rate and compared that rate to the estimated local recurrence rate after radical prostatectomy (RP). Methods and Materials: A prospective database was maintained with clinical, dosi- metric, and outcome data for all LDR-PB implantation procedures performed at our institution. From 1998 to 2008, 2223 patients with prostate cancer received LDR- PB without supplemental external beam radiation therapy. Patients who developed Phoenix-defined biochemical failure were reviewed for sites of relapse and investiga- tions completed. Results: At a median follow-up of 5 years, 108 of 2223 patients (4.8%) developed biochemical relapse. In 1 additional patient, local relapse was found on transurethral prostate resection, but his prostate-specific antigen concentration was well short of triggering Phoenix-defined failure. Of the 109 patients with disease relapse, 18 of 2223 (0.8%) had a proven local recurrence, and 30 of 2223 (1.3%) had a proven distant Reprint requests to: W. James Morris, MD, FRCPC, Department of Radiation Oncology, BC Cancer Agency Vancouver Centre, 600 W 10th Ave, Vancouver, BC, Canada V5Z 4E6. Tel: (604) 877-6000, ext. 2673; E-mail: JMorris@bccancer.bc.ca Conflict of interest: Dr Morris has received educational and research grants from Sanofi-Aventis and Oncura and speaker’s fees from Varian. Dr Pickles has received grants from Sanofi, Canadian Association of Radia- tion Oncology (CARO)/Abbott ACURA Uro-Oncologic Radiation Award and Oncura, and personal fees from Amgen, Astellas, Diagnostic Solutions and Results, Inc., Ferring, GlaxoSmithKline, and Janssen. Dr Keyes received a grant from CARO/Abbott ACURA Uro-Oncologic Radiation Award and funds for the Provincial Prostate Brachytherapy Program from Ferring Pharmaceuticals, Oncura, Janssen, and Abbott. Dr McKenzie has served on advisory boards for Sanofi-Aventis, Astra Zeneca, and Abbvie; has received educational grants from Sanofi-Aventis, Astra Zeneca, Abb- vie, Janssen Ortho, Amgen, Purdue Frederick, and Novartis; and has received honoraria from Varian and Brainlab. Dr Tyldesley has received grants from CARO/Abbott ACURA Uro-Oncologic Radiation Award, and speaker’s and advisory board fees from Astellas, Janssen, Amgen, Abbvie, Ferring Pharmaceuticals, Sanofi-Aventis, and Bayer. Dr Lo has nothing to disclose. AcknowledgmentsdWe acknowledge Jeremy Hamm, Department of Population Oncology, BC Cancer Agency Vancouver Centre, for assistance and advice with statistical reporting. Int J Radiation Oncol Biol Phys, Vol. 91, No. 4, pp. 745e751, 2015 0360-3016/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ijrobp.2014.12.014 Radiation Oncology International Journal of biology physics www.redjournal.org