Moderate dose escalation with single-fraction highedose rate brachytherapy boost for clinically localized intermediate- and high-risk prostate cancer: 5-year outcome of the first 100 consecutively treated patients P eter  Agoston 1, * , Tibor Major 1 , Georgina Fr€ ohlich 1 , Zolt  an Szab o 1 ,J ozsef L€ ovey 1 , J anos Fodor 1 , Mikl os K asler 2 , Csaba Polg ar 1 1 Department of Radiotherapy, National Institute of Oncology, Budapest, Hungary 2 National Institute of Oncology, Budapest, Hungary ABSTRACT PURPOSE: To analyze the clinical outcome and toxicity data of the first 100 consecutive patients treated with a single-fraction highedose rate brachytherapy (HDR-BT) and external beam radio- therapy (EBRT). METHODS AND MATERIALS: Two-hundred eighty patients have been treated with HDR-BT boost for localized intermediate- to high-risk prostate cancer. Among these, the outcome and toxicity of the first 100 patients treated with a single HDR-BT fraction were assessed. A median dose of 60 Gy EBRT was given to the prostate and vesicles. Interstitial HDR-BT of 10 Gy was per- formed during the course of EBRT. RESULTS: Median followup time was 61.5 months. The 5-year actuarial rates of overall survival, cause-specific survival, disease-free survival, and biochemical no evidence of disease (bNED) for the entire cohort were 93.3%, 99.0%, 89.3%, and 85.5%, respectively. The 7-year actuarial rate of bNED was 84.2% for the intermediate-risk group and 81.6% for the high-risk group ( p 5 0.8464). The 7-year actuarial rates of bNED for Grade 1, 2, and 3 tumors were 97.5%, 80.0%, and 67.1%, respectively. The 5-year probability for developing late Grade 3 gastrointestinal and genitourinary (GU) toxicity was 2.1% and 14.4%, respectively. Grade 3 GU complications occurred significantly more frequently in patients with a history of preirradiation transurethral resection (29.1% vs. 8.8%; p 5 0.0047). CONCLUSIONS: Five-year outcome after 60 Gy EBRT plus a single fraction of 10 Gy HDR-BT boost is encouraging. Preradiation transurethral resection significantly increases the risk of late severe GU complications. Ó 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved. Keywords: Prostate cancer; Highedose rate brachytherapy; Boost; External beam radiotherapy Introduction The optimal treatment for intermediate- and high-risk clinically localized or locally advanced prostate cancer remains undefined. Studies using dose escalation with external beam radiotherapy (EBRT) showed that doses more than 70 Gy in 2 Gy fractions significantly increased biochemical and clinical freedom from failure in T1eT3 localized prostate cancer (1). Other investigators using highedose rate brachytherapy (HDR-BT) as a boost showed that there is a strong doseeresponse relationship for intermediate- to high-risk prostate cancer patients, and improved locoregional control with higher radiation doses alone can significantly decrease the incidence of biochem- ical and clinical failures (2). Use of HDR-BT as a means of dose escalation in prostate cancer is based on the hypoth- esis that treatment delivery with high fractional doses will exploit the presumed fractionation sensitivity of prostate Received 16 November 2010; accepted 4 January 2011. * Corresponding author. Department of Radiotherapy, National Insti- tute of Oncology, R ath Gy. u. 7-9., H-1122 Budapest, Hungary. Tel.: þ36-1-224-8600; fax: þ36-1-224-8680. E-mail address: agoston.p@oncol.hu (P.  Agoston). 1538-4721/$ - see front matter Ó 2011 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved. doi: 10.1016/j.brachy.2011.01.003 Brachytherapy - (2011) -