PD10-07 PREDICTORS OF RADIOGRAPHIC PROGRESSION IN METASTATIC CASTRATION-RESISTANT PROSTATE CANCER PATIENTS TREATED WITH ABIRATERONE: RETROSPECTIVE ANALYSIS OF COU-AA-302

Abstract

You have accessJournal of UrologyProstate Cancer: Advanced (including Drug Therapy) I1 Apr 2018PD10-07 PREDICTORS OF RADIOGRAPHIC PROGRESSION IN METASTATIC CASTRATION-RESISTANT PROSTATE CANCER PATIENTS TREATED WITH ABIRATERONE: RETROSPECTIVE ANALYSIS OF COU-AA-302 Lisa Martin, Shabbir Alibhai, Maria Komisarenko, Narhari Timilshina, and Antonio Finelli Lisa MartinLisa Martin More articles by this author , Shabbir AlibhaiShabbir Alibhai More articles by this author , Maria KomisarenkoMaria Komisarenko More articles by this author , Narhari TimilshinaNarhari Timilshina More articles by this author , and Antonio FinelliAntonio Finelli More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.617AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Radiographic imaging is used to monitor disease progression for men with metastatic castrate resistant prostate cancer (mCRPC) to make decisions about their treatment. Information about the optimal frequency of imaging is important because imaging is costly and access may be limited. We sought to identify predictors of radiographic progression that could be used in clinic to inform the frequency of imaging for men with mCRPC. METHODS We accessed data for men with chemo-naive mCRPC in the abiraterone treatment group of a phase III randomized trial (COU-AA-302) (n=546) through the Yale University Open Data Access Project. The outcome measure was time from randomization to radiographic progression in bone and/or soft tissue (n=301 events). We used univariable and multivariable Cox proportional hazards modelling to identify predictors of time to progression. We then divided the subjects into 6 risk strata based on the 2 variables most strongly associated with progression and estimated the probability of radiographic progression free survival (RPFS) at 6 and 12 months after starting abiraterone. RESULTS The median time to radiographic progression was 16.6 months (95% confidence interval (CI) of 14.4 to 19.3 months). A model containing baseline variables (extent of disease, ECOG status, pain, prostate specific antigen (PSA), lactate dehydrogenase, alkaline phosphate (ALP) and albumin) and change in PSA and ALP at 8 weeks had a concordance statistic of 0.71. Extent of disease at baseline and change in PSA at 8 weeks were the strongest independent determinants of RPFS. The probability of RPFS for men with bone only disease at baseline and a >= 50% fall in PSA (32% of all subjects, lowest risk stratum) was 93% (95% CI 87 to 96) at 6 months and 80% (95% CI 72 to 86) at 12 months. In contrast, the probability of RPFS for men with bone and soft metastasis at baseline and < 50% fall in PSA (13% of all subjects, highest risk stratum) was 55% (95% CI 41 to 67) at 6 months and 34% (95% CI 22 to 47) at 12 months. CONCLUSIONS Patients with chemo-naive mCRPC treated with abiraterone can be divided into groups with significantly different risks of radiographic progression based on a few clinically available variables. These results suggest that the imaging schedule for these patients could be individualized. This finding should be externally validated, and examined with other treatments, and may ultimately lead to more efficient use of imaging in men with mCRPC. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e230 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Lisa Martin More articles by this author Shabbir Alibhai More articles by this author Maria Komisarenko More articles by this author Narhari Timilshina More articles by this author Antonio Finelli More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...