doi:10.1016/j.ijrobp.2006.10.012 CLINICAL INVESTIGATION Prostate FEASIBILITY OF HIGH-DOSE-RATE BRACHYTHERAPY SALVAGE FOR LOCAL PROSTATE CANCER RECURRENCE AFTER RADIOTHERAPY: THE UNIVERSITY OF CALIFORNIA–SAN FRANCISCO EXPERIENCE BRIAN LEE, M.D., PH.D.,* KATSUTO SHINOHARA, M.D., † VIVIAN WEINBERG,PH.D., ‡ ALEXANDER R. GOTTSCHALK, M.D., PH.D.,* JEAN POULIOT,PH.D.,* MACK ROACH III, M.D.,* AND I-CHOW HSU, M.D.* *Department of Radiation Oncology, University of California–San Francisco, San Francisco, CA and † Department of Urology, University of California–San Francisco, San Francisco, CA, and ‡ Comprehensive Cancer Center Biostatistics Core, University of California–San Francisco, San Francisco, CA Purpose: The aim of this study was to evaluate the feasibility and safety of salvage high-dose-rate (HDR) brachytherapy for locally recurrent prostate cancer after external beam radiotherapy (EBRT). Methods and Materials: We retrospectively analyzed 21 consecutively accrued patients undergoing salvage HDR brachytherapy for locally recurrent prostate cancer after EBRT between November 1998 and December 2005. After pathologic confirmation of locally recurrent disease, all patients were treated with 36 Gy in six fractions using two transrectal ultrasound– guided HDR prostate implants, separated by 1 week. Eleven patients received neoadjuvant hormonal therapy immediately presalvage, whereas none received adjuvant hormonal therapy postsalvage. Median follow-up time from recurrence was 18.7 months (range, 6 – 84 months). Determination of subsequent biochemical failure after brachytherapy was based on the definition by the American Society for Therapeutic Radiology and Oncology. Results: Based on the Common Terminology Criteria for Adverse Events (CTCAE version 3), 18 patients reported Grade 1 to 2 genitourinary symptoms by 3 months postsalvage. Three patients developed Grade 3 genitourinary toxicity. Maximum observed gastrointestinal toxicity was Grade 2; all cases spontaneously resolved. The 2-year Kaplan-Meier estimate of biochemical control after recurrence was 89%. Thirteen patients have achieved a PSA nadir <0.1 ng/ml, but at the time of writing this endpoint has not yet been reached for all patients. All patients are alive; however 2 have experienced biochemical failure, both with PSA nadirs >1, and have subsequently been found to have distant metastases. Conclusions: Salvage HDR prostate brachytherapy appears to be feasible and effective. © 2007 Elsevier Inc. High-dose-rate brachytherapy, Salvage, Radiation failure, Prostate, Recurrence. INTRODUCTION For prostate cancer patients who subsequently develop bio- chemical failure after radiotherapy, there are a number of treatment options in addition to radical prostatectomy and hormonal therapy. These options include cryoablation, ther- moablation, and brachytherapy (both low-dose-rate [LDR] and high-dose-rate [HDR]). Of these techniques, prostatec- tomy and cryotherapy are perhaps the most widely used, but brachytherapy has garnered much interest because of recent technologic developments in this field. The characteristics of suitable salvage LDR brachytherapy patients include those with the following: lack of distant disease by radio- graphic or clinical detection; biopsy confirmation of local disease; prolonged initial disease free interval (2 years) between primary treatment and recurrence; prostate-specific antigen (PSA) doubling time 9 months; Gleason score at salvage 6; PSA 10 ng/ml; no extracapsular extension; and no seminal vesicle invasion (1). Many patients do not meet all criteria, and how to treat this subset of patients is a particular challenge in oncology today. Difficulties reported for the permanent seed LDR brachytherapy techniques in- clude: the inability to reliably implant the seminal vesicles and extracapsular extension; the inability to reposition seeds once placed; and seed migration in 5% to 10% of patients (2). High-dose-rate brachytherapy does not share these lim- itations and also has the advantages of delivering a highly conformal dose distribution, accurate dosimetry, elimina- tion of radiation exposure to hospital staff and family mem- bers (3). With these advantages in mind, the University of California–San Francisco began using HDR brachytherapy Reprint requests to: I-C. Hsu, M.D., 1600 Divisadero Street, Suite #H1032, Radiation Oncology Department, San Francisco, CA 94115. Tel: (415) 353-7106; Fax: (415) 353-9883; E-mail: Hsu@radonc17.ucsf.edu Conflict of interest: none. Received July 27, 2006, and in revised form Oct 11, 2006. Accepted Oct 17, 2006. Int. J. Radiation Oncology Biol. Phys., Vol. 67, No. 4, pp. 1106 –1112, 2007 Copyright © 2007 Elsevier Inc. Printed in the USA. All rights reserved 0360-3016/07/$–see front matter 1106