title: Development and external validation of an extended repeat biopsy nomogram.
abstract: OBJECTIVE
  We hypothesized that the outcome of repeat biopsy could be accurately predicted. We tested this hypothesis in a contemporary cohort from 3 centers.
  
  
  METHODS
  The principal cohort of 1,082 men from Hamburg, Germany was used for nomogram development as well as for internal 200 bootstrap validation in 721 and external validation in 361. Two additional external validation cohorts, including 87 men from Milan, Italy and 142 from Seattle, Washington, were also used. Predictors of prostate cancer on repeat biopsy were patient age, digital rectal examination, prostate specific antigen, percent free prostate specific antigen, number of previous negative biopsy sessions and sampling density. Multivariate logistic regression models were used to develop the nomograms.
  
  
  RESULTS
  The mean number of previous negative biopsies was 1.5 (range 1 to 6) and the mean number of cores at final repeat biopsy was 11.1 (range 10 to 24). Of the men 370 (30.2%) had prostate cancer. On multivariate analyses all predictors were statistically significant (p < or =0.028). After internal validation the nomogram was 76% accurate. External validation showed 74% (Hamburg), 78% (Milan) and 68% (Seattle) accuracy.
  
  
  CONCLUSIONS
  Relative to the previous nomograms (10 predictors or 71% accuracy) our tool relies on fewer variables (6) and shows superior accuracy in European men. Accuracy in American men is substantially lower. Racial, clinical and biochemical differences may explain the observed discrepancy in predictive accuracy.
authors.affiliation: Cancer Prognostics and Health Outcomes Unit, University of Montreal, Montreal, Quebec, Canada.
authors.forename: Felix K-H
authors.initials: FK
authors.lastname: Chun
authors.forename: Alberto
authors.initials: A
authors.lastname: Briganti
authors.forename: Markus
authors.initials: M
authors.lastname: Graefen
authors.forename: Christopher
authors.initials: C
authors.lastname: Porter
authors.forename: Francesco
authors.initials: F
authors.lastname: Montorsi
authors.forename: Alexander
authors.initials: A
authors.lastname: Haese
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Scattoni
authors.forename: Lester
authors.initials: L
authors.lastname: Borden
authors.forename: Thomas
authors.initials: T
authors.lastname: Steuber
authors.forename: Andrea
authors.initials: A
authors.lastname: Salonia
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schlomm
authors.forename: Kalyan
authors.initials: K
authors.lastname: Latchemsetty
authors.forename: Jochen
authors.initials: J
authors.lastname: Walz
authors.forename: Jason
authors.initials: J
authors.lastname: Kim
authors.forename: Christian
authors.initials: C
authors.lastname: Eichelberg
authors.forename: Eike
authors.initials: E
authors.lastname: Currlin
authors.forename: Sascha A
authors.initials: SA
authors.lastname: Ahyai
authors.forename: Andreas
authors.initials: A
authors.lastname: Erbersdobler
authors.forename: Luc
authors.initials: L
authors.lastname: Valiquette
authors.forename: Hans
authors.initials: H
authors.lastname: Heinzer
authors.forename: Patrizio
authors.initials: P
authors.lastname: Rigatti
authors.forename: Hartwig
authors.initials: H
authors.lastname: Huland
authors.forename: Pierre I
authors.initials: PI
authors.lastname: Karakiewicz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D011471:Prostatic Neoplasms / Q000473:pathology*