title: External validation of the cancer of the prostate risk assessment score to predict biochemical relapse after radical prostatectomy for prostate cancer in Japanese patients.
abstract: OBJECTIVE
  The aim of the present study was external validation to determine whether the Cancer of the Prostate Risk Assessment (CAPRA) score predicts biochemical relapse (BCR) after radical prostatectomy (RP) in Japanese patients.
  
  
  METHODS
  From 1995 to 2008, 503 Japanese patients undergoing RP for clinically localized prostate cancer were included in the validation cohort. The BCR-free rate was estimated using the Kaplan-Meier method. Performance of the CAPRA score was assessed using Cox proportional hazards regression models, concordance index (c-index) and calibration plots.
  
  
  RESULTS
  Unlike the results in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) cohort, the BCR-free rate and the hazard ratio for CAPRA score 4 were inversely better than those for CAPRA scores 2 and 3 in Japanese patients. The c-index of the CAPRA score was 0.673. The calibration plot demonstrated that the CAPRA score was generally well calibrated.
  
  
  CONCLUSIONS
  In Japanese patients, the CAPRA score can predict BCR after RP only to some degree. Although our c-index is comparable with the c-index of 0.66 in the original CaPSURE cohort, it is lower than the c-indices reported in other validation cohorts, which range from 0.68 to 0.81. The CAPRA score may not predict BCR after RP in Japanese patients as accurately as it did in Western patients.
authors.affiliation: Department of Urology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Japan. takahiro-y@sannet.ne.jp
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yoshida
authors.forename: Masashi
authors.initials: M
authors.lastname: Nakayama
authors.forename: Ken
authors.initials: K
authors.lastname: Takeda
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Arai
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kakimoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nishimura
mesh_terms: D000368:Aged; D044466:Asian People; D001706:Biopsy; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D006801:Humans; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000208:ethnology / Q000473:pathology / Q000601:surgery*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen