1501 ESTABLISHING A THRESHOLD FOR PSA DOUBLING TIME IN PREDICTING OUTCOMES FOLLOWING SALVAGE RADIATION THERAPY (2013)

You have accessJournal of UrologyProstate Cancer: Localized (VII)1 Apr 20131501 ESTABLISHING A THRESHOLD FOR PSA DOUBLING TIME IN PREDICTING OUTCOMES FOLLOWING SALVAGE RADIATION THERAPY Todd Morgan, William C. Jackson, Skyler Johnson, David C. Miller, Jeffrey S. Montgomery, James E. Montie, Alon Z. Weizer, Ted A. Skloarus, Brent K. Hollenbeck, Ganesh S. Palapattu, Daniel A. Hamstra, and Felix Y. Feng Todd MorganTodd Morgan Ann Arbor, MI More articles by this author , William C. JacksonWilliam C. Jackson Ann Arbor, MI More articles by this author , Skyler JohnsonSkyler Johnson Ann Arbor, MI More articles by this author , David C. MillerDavid C. Miller Ann Arbor, MI More articles by this author , Jeffrey S. MontgomeryJeffrey S. Montgomery Ann Arbor, MI More articles by this author , James E. MontieJames E. Montie Ann Arbor, MI More articles by this author , Alon Z. WeizerAlon Z. Weizer Ann Arbor, MI More articles by this author , Ted A. SkloarusTed A. Skloarus Ann Arbor, MI More articles by this author , Brent K. HollenbeckBrent K. Hollenbeck Ann Arbor, MI More articles by this author , Ganesh S. PalapattuGanesh S. Palapattu Ann Arbor, MI More articles by this author , Daniel A. HamstraDaniel A. Hamstra Ann Arbor, MI More articles by this author , and Felix Y. FengFelix Y. Feng Ann Arbor, MI More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.2980AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES For patients receiving salvage external beam radiation therapy (SRT) for a rising serum prostate specific antigen (PSA) following radical prostatectomy (RP), a short PSA doubling time (PSADT) after RP is known to predict worse clinical outcomes. Various PSADT thresholds have been proposed, but the most clinically prognostic threshold is not well established. We sought to define the ideal PSADT threshold. METHODS Through an IRB approved retrospective analysis, 575 patients who underwent SRT following RP at the University of Michigan from 1986-2008 were reviewed. Outcomes of interest included biochemical failure (BF), prostate cancer-specific mortality (PCSM), development of distant metastasis (DM), and overall survival (OS). Kaplan-Meier methods, cubic splines, and Cox Proportional Hazard models were used to evaluate an ideal PSADT threshold. RESULTS Sufficient data to calculate PSADTs were available for 277 patients. Median follow up was 82.9 months. PSADT after RP was analyzed as a continuous variable, and the c-index was determined for BF (0.62), DM (0.67), PCSM (0.72), and OS (0.64). PSADT was next analyzed to determine the most appropriate threshold. Patients with PSADTs ≤ 3, 3-6, 6-10, and >10 months were compared. Patients with PSADT ≤ 3 and 3-6 months had similar rates of BF, DM, PCSM, and OS, as did patients with a PSADT of 6-10 and > 10 months. However, patients with a PSADT of 3-6 months were significantly more likely to experience BF (p<0.01 HR: 2.2 [95%CI: 1.4-3.5]) and DM (p=0.02 HR: 2.2 [95%CI: 1.2-4.3]) than patients with a PSADT of 6-10 months. To further investigate various thresholds, we calculated HR's for a range of thresholds from 2-12 months for BF, DM, PCMS, and OS. The estimated HR's were then plotted versus threshold values, and cubic splines were used to smooth the HR's. This again selected 6 months as the ideal threshold for distinguishing patients at highest risk for BF (p<0.01 HR: 2.3 [95%CI: 1.6-3.3]) and DM (p<0.01 HR: 2.78 [95%CI: 1.7-4.6]). An ideal cut-point was not obvious using this method for PCSM or OS. On multivariate analysis, a threshold of 6 months strongly predicted BF (p<0.01 HR: 2.1 [95%CI: 1.5-3.0]), DM (p=0.01 HR: 2.0 [95%CI: 1.2-3.4]), and PCSM (p=0.04 HR: 2.3 [95%CI: 1.1-5.2]). CONCLUSIONS A PSADT ≤ 6 months appears to be an ideal threshold for defining patients at highest risk for BF, and DM following SRT, and strongly predicted BF, DM, and PCSM on multivariate analysis in our dataset. These data suggest that patients with a PSADT ≤ 6 months may benefit from intensification of salvage treatment. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e615-e616 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Todd Morgan Ann Arbor, MI More articles by this author William C. Jackson Ann Arbor, MI More articles by this author Skyler Johnson Ann Arbor, MI More articles by this author David C. Miller Ann Arbor, MI More articles by this author Jeffrey S. Montgomery Ann Arbor, MI More articles by this author James E. Montie Ann Arbor, MI More articles by this author Alon Z. Weizer Ann Arbor, MI More articles by this author Ted A. Skloarus Ann Arbor, MI More articles by this author Brent K. Hollenbeck Ann Arbor, MI More articles by this author Ganesh S. Palapattu Ann Arbor, MI More articles by this author Daniel A. Hamstra Ann Arbor, MI More articles by this author Felix Y. Feng Ann Arbor, MI More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...