title: International validation of a preoperative nomogram for prostate cancer recurrence after radical prostatectomy.
abstract: OBJECTIVE
  We evaluated the predictive accuracy of a recently published preoperative nomogram for prostate cancer that predicts 5-year freedom from recurrence. We applied this nomogram to patients from seven different institutions spanning three continents.
  
  
  METHODS
  Clinical data of 6,754 patients were supplied for validation, and 6,232 complete records were used. Nomogram-predicted probabilities of 60-month freedom from recurrence were compared with actual follow-up in two ways. First, areas under the receiver operating characteristic curves (AUCs) were determined for the entire data set according to several variables, including the institution where treatment was delivered. Second, nomogram classification-based risk quadrants were compared with actual Kaplan-Meier plots.
  
  
  RESULTS
  The AUC for all institutions combined was 0.75, with individual institution AUCs ranging from 0.67 to 0.83. Nomogram predictions for each risk quadrant were similar to actual freedom from recurrence rates: predicted probabilities of 87% (low-risk group), 64% (intermediate-low-risk group), 39% (intermediate-high-risk group), and 14% (high-risk group) corresponded to actual rates of 86%, 64%, 42%, and 17%, respectively. The use of neoadjuvant therapy, variation in the prostate-specific antigen recurrence definitions between institutions, and minor differences in the way the Gleason grade was reported did not substantially affect the predictive accuracy of the nomogram.
  
  
  CONCLUSIONS
  The nomogram is accurate when applied at international treatment institutions with similar patient selection and management strategies. Despite the potential for heterogeneity in patient selection and management, most predictions demonstrated high concordance with actual observations. Our results demonstrate that accurate predictions may be expected across different patient populations.
authors.affiliation: Department of Urology, Division of Solid Tumor Oncology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA.
authors.forename: Markus
authors.initials: M
authors.lastname: Graefen
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
authors.forename: Ilias
authors.initials: I
authors.lastname: Cagiannos
authors.forename: David I
authors.initials: DI
authors.lastname: Quinn
authors.forename: Susan M
authors.initials: SM
authors.lastname: Henshall
authors.forename: John J
authors.initials: JJ
authors.lastname: Grygiel
authors.forename: Robert L
authors.initials: RL
authors.lastname: Sutherland
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Stricker
authors.forename: Eric
authors.initials: E
authors.lastname: Klein
authors.forename: Patrick
authors.initials: P
authors.lastname: Kupelian
authors.forename: Donald G
authors.initials: DG
authors.lastname: Skinner
authors.forename: Gary
authors.initials: G
authors.lastname: Lieskovsky
authors.forename: Bernard
authors.initials: B
authors.lastname: Bochner
authors.forename: Hartwig
authors.initials: H
authors.lastname: Huland
authors.forename: Peter G
authors.initials: PG
authors.lastname: Hammerer
authors.forename: Alexander
authors.initials: A
authors.lastname: Haese
authors.forename: Andreas
authors.initials: A
authors.lastname: Erbersdobler
authors.forename: James A
authors.initials: JA
authors.lastname: Eastham
authors.forename: Jean
authors.initials: J
authors.lastname: de Kernion
authors.forename: Thomas
authors.initials: T
authors.lastname: Cangiano
authors.forename: Fritz H
authors.initials: FH
authors.lastname: Schröder
authors.forename: Mark F
authors.initials: MF
authors.lastname: Wildhagen
authors.forename: Theo H
authors.initials: TH
authors.lastname: van der Kwast
authors.forename: Peter T
authors.initials: PT
authors.lastname: Scardino
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kattan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery*; D012372:ROC Curve; D012307:Risk Factors; D016019:Survival Analysis