title: CAPRA-S predicts outcome for adjuvant and salvage external beam radiotherapy after radical prostatectomy.
abstract: BACKGROUND
  We aimed to evaluate the predictive value of the Cancer of the Prostate Risk Assessment Postsurgical Score (CAPRA-S) for patients treated with radical prostatectomy followed by subsequent external beam radiotherapy (EBRT).
  
  
  METHODS
  A total of 373 patients treated with EBRT between January 2000 and June 2015 were identified in the institutional database. Followup and complete CAPRA-S score were available for 334 (89.5%) patients. CAPRA-S scores were sorted into previously defined categories of low- (score 0-2), intermediate- (3-5), and high-risk (6-12). Time to biochemical recurrence (BCR) was defined as prostate-specific antigen (PSA) >0.20 ng/mL after EBRT. Survival analyses were performed using the Kaplan-Meier method and comparisons were made using the log-rank test.
  
  
  RESULTS
  Overall median time from surgery to EBRT was 18 months (interquartile range [IQR] 8-36) and median followup since EBRT was 48 months (IQR 28-78). CAPRA-S predicted time to BCR (<0.001), time to palliative androgen-deprivation therapy (ADT) (p=0.017), and a trend for significantly predicting overall survival (OS, p=0.058). On multivariate analysis, the CAPRA-S was predictive of time to BCR only (low-risk vs. intermediate-risk; hazard ratio [HR] 0.14, 95% confidence interval [CI] 0.043-0.48, p=0.001). The last PSA measurement before EBRT as a continuous and grouped variable proved highly significant in predicting all outcomes tested, including OS (p≤0.002).
  
  
  CONCLUSIONS
  CAPRA-S predicts time to BCR and freedom from palliative ADT, and is borderline significant for OS. Together with the PSA before EBRT, CAPRA-S is a useful, predictive tool. The main limitation of this study is its retrospective design.
authors.affiliation: Department of Radiation Oncology, Centre hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montreal, QC, Canada;
authors.forename: Michel
authors.initials: M
authors.lastname: Zimmermann
authors.affiliation: Department of Radiation Oncology, Centre hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montreal, QC, Canada;; CRCHUM-Centre de recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada;
authors.forename: Guila
authors.initials: G
authors.lastname: Delouya
authors.affiliation: Section of Urology, Department of Surgery, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Alenizi
authors.affiliation: Section of Urology, Department of Surgery, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
authors.forename: Emad
authors.initials: E
authors.lastname: Rajih
authors.affiliation: Section of Urology, Department of Surgery, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Zorn
authors.affiliation: Department of Radiation Oncology, Centre hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montreal, QC, Canada;; CRCHUM-Centre de recherche du Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada;
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky