title: External validation of a preoperative nomogram for prediction of the risk of recurrence after radical prostatectomy.
abstract: OBJECTIVE
  To test the validity of an updated version of the preoperative Kattan nomogram for prediction of recurrence after radical prostatectomy (RP), published by Stephenson et al.
  
  
  METHODS
  We relied on clinical and postoperative prostate-specific antigen follow-up data of 1978 patients treated with open RP at our institution between 1992 and 2006. The accuracy of the nomogram-derived recurrence-free survival predictions were separately tested at 1 to 10 years after RP. Moreover, the relationship between the nomogram-predicted recurrence-free survival rate and the observed recurrence-free survival rate was graphically explored in calibration plots.
  
  
  RESULTS
  Median follow-up of censored patients was 32 months. For nomogram-derived recurrence-free survival predictions at 1 to 10 years, the accuracy of the nomogram ranged from 70% to 76%. The calibration between the predicted and observed recurrence-free survival rates was good at 1 and 2 years after RP. However, at all other examined time points, departures from ideal predictions were recorded.
  
  
  CONCLUSIONS
  Our findings indicate that the preoperative biochemical recurrence nomogram reported by Stephenson et al. can be applied to European patients with good accuracy. However, its calibration was only suboptimal for predictions made 3 or more years after RP, with a tendency to overestimate the probability of recurrence-free survival. This potential limitation should be considered when this tool is applied to European patients.
authors.affiliation: Martiniclinic, Prostate Cancer Center Hamburg-Eppendorf, Hamburg, Germany. hendrikisbarn@gmail.com
authors.forename: Hendrik
authors.initials: H
authors.lastname: Isbarn
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
authors.forename: Jochen
authors.initials: J
authors.lastname: Walz
authors.forename: Sascha A
authors.initials: SA
authors.lastname: Ahyai
authors.forename: Thomas
authors.initials: T
authors.lastname: Steuber
authors.forename: Alexander
authors.initials: A
authors.lastname: Haese
authors.forename: Lars
authors.initials: L
authors.lastname: Budäus
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schlomm
authors.forename: Christian
authors.initials: C
authors.lastname: Eichelberg
authors.forename: Roman
authors.initials: R
authors.lastname: Heuer
authors.forename: Hans
authors.initials: H
authors.lastname: Heinzer
authors.forename: Hartwig
authors.initials: H
authors.lastname: Huland
authors.forename: Markus
authors.initials: M
authors.lastname: Graefen
authors.forename: Felix K H
authors.initials: FK
authors.lastname: Chun
mesh_terms: D019540:Area Under Curve; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local; D049451:Nomograms; D011336:Probability; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery*; D013997:Time Factors
chemical_list: D017430:Prostate-Specific Antigen