Long-Term Outcomes of Patients With High-Risk Prostate Cancer Treated With HDR Brachytherapy Boost

Abstract

Purpose/Objective(s): To report the long-term clinical outcomes of patients with high-risk adenocarcinoma of the prostate treated with pelvic radiation therapy followed by high-dose-rate (HDR) brachytherapy boost. Materials/Methods: 115 consecutive patients with high-risk prostate cancer ( cT3, Gleason (GS) 8-10, or PSA 20) treated between July 1997 and November 2005 were included in this study. All patients underwent whole pelvic radiation therapy to 45 Gy followed by HDR brachytherapy boost. HDR brachytherapy boost consisted of 6 Gy x 3 (38 patients) or 9.5 Gy x 2 (77 patients) to the prostate and seminal vesicles. 47%, 48%, and 5 % patients received long-term (>18 mos), short-term (4-6 mos), or no androgen deprivation therapy, respectively. Results: The median age at diagnosis was 64.8 yrs. 50 (43%), 90 (78.2%), and 24 (20.8%) patients were diagnosed with GS 8-10, cT3 disease, and PSA 20, respectively. Mean PSA was 14.94 (range 0.21-99.3). 21 patients (18.2%) had seminal vesicle invasion and 42 patients (37%) had at least 2 high-risk features. With a median follow-up time of 94 months, biochemical free survival as defined by the Phoenix definition was 78.2%. 4 patients (3.5%) failed locally as determined by biopsy without metastatic disease. Overall survival and disease specific survival were 84.3% and 95.7%, respectively. Six secondary malignancies (bladder 1 year posttreatment, colon, lung, melanoma, hepatocellular carcinoma) developed. One patient developed grade 3 ureteral stricture causing hydronephrosis and required stent placement. There were no other grade 3 or greater genitourinary or gastrointestinal toxicity. Conclusions: Pelvic radiation therapy followed by HDR brachytherapy boost is an effective treatment for high-risk prostate cancer with excellent long-term disease control and minimal toxicity. Author Disclosure: A.J. Chang: None. M. Roach: None. A. Gottschalk: None. A.J. Cunha: None. Z.A. Seymour: None. J.A. Johnson: None. D. Raleigh: None. K. Shinohara: None. I.J. Hsu: None.