MP53-08 LONG-TERM OUTCOMES OF MEN WITH A POSITIVE BIOPSY FOLLOWING PROSTATE BRACHYTHERAPY

Abstract

You have accessJournal of UrologyProstate Cancer: Localized: Radiation Therapy (MP53)1 Apr 2020MP53-08 LONG-TERM OUTCOMES OF MEN WITH A POSITIVE BIOPSY FOLLOWING PROSTATE BRACHYTHERAPY Nelson N. Stone* and Richard Stock Nelson N. Stone*Nelson N. Stone* More articles by this author and Richard StockRichard Stock More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000915.08AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: To determine the factors associated with a positive biopsy and the effects of local failure on biochemical control and cause-specific survival (CSS) in men receiving prostate brachytherapy. METHODS: 2319 men underwent prostate brachytherapy ± hormone therapy (HT) ± external beam radiation and were followed a mean of 9.1 years (range 5-22). Median age and PSA were 66 years and 6.8 ng/ml. 987 (42.6%) were low, 907 (39.1%) intermediate and 425 (18.3%) high risk. HT was used in 1263 (54.5%) for a median of 6 months. 545 men agreed to 12-core TRUS biopsy a median of 25 months after completion of all therapy which was repeated in 114 at median of 64 months after treatment. Post-implant radiation doses were converted to the biologic equivalent dose (BED) using an α/β of 2. Associations of biopsy results with PSA, clinical stage (CS), Gleason grade group (GG), time on HT and BED were determined by ANOVA (bootstrap), chi-square and binary linear regression (LR). Survival was estimated for biopsy results for freedom from Phoenix failure (PHxF) and CSS using Kaplan Meier method and Cox proportions hazard rates. RESULTS: Higher PSA (13.9 vs 10.1 ng/ml, p=0.05), CS (p=0.034), less HT (p=0.010) and lower BED (158.8 vs. 181 Gy, p<0.001) was associated with a positive biopsy (n= 59,10.8%). Significant coefficients by LR were HT (p=0.005), CS (p=0.044) and BED (p=0.030). Of the 114 repeat biopsies, 16 neg. became pos., 27 pos. became neg., 22 were initially pos. but were not repeated and 13 developed failure. The last biopsy status was 48/545 (8.8%) as positive. While PSA, CS, HT and BED remained significant on univariate analysis, only BED was significant on LR (p<0.001). Positive biopsy was 17/112 (15.2%), 14/230 (6.1%) and 3/182 (1.6%) for BED ≤ 150, >150-200 and > 200 Gy (p<0.001), respectively. Median BED was 185 Gy and 29/261 (11.1%) vs. 5/263 (1.9%) has positive biopsy for lower vs. higher dose (OR 5.8, p<0.001). In men with GG>1, positive bx was 9/66 (13.6%) vs, 1/64 (1.6%) for BED ≤ 185 Gy vs. more (p=0.01, OR 8.7). For neg. vs. pos. biopsy 15-year PHxF was 75.6 vs. 17.5% and CSS was 94.2 vs. 75.5% (Figures, p<0.001). CONCLUSIONS: High radiation dose (BED > 185 Gy) is associated with a 1.9% positive biopsy rate following brachytherapy including men with high grade disease. Local failure is associated with substantially higher biochemical failure and worse prostate cancer survival. Source of Funding: none © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e784-e785 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nelson N. Stone* More articles by this author Richard Stock More articles by this author Expand All Advertisement PDF downloadLoading ...