title: Low predictive accuracy of the Kattan postoperative nomogram for renal cell carcinoma recurrence in a population of French patients.
abstract: BACKGROUND
  The aim of the current study was to establish the predictive accuracy of the Kattan postoperative nomogram for nonmetastatic renal cell carcinoma (RCC) by comparing predictions with actual disease recurrence in patients who underwent surgery in a single center in France.
  
  
  METHODS
  Between 1985 and 2000, 844 patients were treated for RCC. The following data were collated: age, symptoms, histology, tumor size, grade, TNM 1997 stage, recurrence, and progression. For each patient a prognostic score (predicted probability) for recurrence-free survival (RFS) at 5 years was calculated using the Kattan nomogram. The discriminating ability of the model was assessed by Harrell's concordance index (c-index). Bootstrapping was used to assess confidence intervals. Furthermore, survival was then estimated by the Kaplan-Meier method and Cox proportional hazards regression analysis.
  
  
  RESULTS
  In all, 565 patients (median age, 62 years) were included. At the time of the last follow-up, 81 patients had died and 101 had experienced RCC recurrence. The c-index for RFS (Kattan nomogram) was only 0.607 (95% confidence interval [CI]: 0.576-0.635). The 5-year RFS rate and cancer-specific survival rate were 81.5% and 84.7%, respectively. Of the 4 variables included in the nomogram, only TNM stage was associated with recurrence in a multivariate analysis (Cox analysis) (P = .022).
  
  
  CONCLUSIONS
  There was a discrepancy between predicted RFS as estimated by the Kattan nomogram and the likelihood of being recurrence-free at 5 years according to the Cox analysis in the current population of patients. However, until new dynamic models become available clinicians may still improve their predictive ability by using the current nomogram.
authors.affiliation: Department of Urology, Necker Hospital, GHU Ouest, University Paris V Rene Descartes, Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Hupertan
authors.forename: Morgan
authors.initials: M
authors.lastname: Roupret
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Poisson
authors.forename: Yves
authors.initials: Y
authors.lastname: Chretien
authors.forename: Bertrand
authors.initials: B
authors.lastname: Dufour
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thiounn
authors.forename: Arnaud
authors.initials: A
authors.lastname: Mejean
mesh_terms: D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D005260:Female; D005602:France; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000473:pathology; D049451:Nomograms; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models