title: A four-kallikrein panel for the prediction of repeat prostate biopsy: data from the European Randomized Study of Prostate Cancer screening in Rotterdam, Netherlands.
abstract: BACKGROUND
  Most men with elevated levels of prostate-specific antigen (PSA) do not have prostate cancer, leading to a large number of unnecessary biopsies. A statistical model based on a panel of four kallikreins has been shown to predict the outcome of a first prostate biopsy. In this study, we apply the model to an independent data set of men with previous negative biopsy but persistently elevated PSA.
  
  
  METHODS
  The study cohort consisted of 925 men with a previous negative prostate biopsy and elevated PSA (>or=3 ng ml(-1)), with 110 prostate cancers detected (12%). A previously published statistical model was applied, with recalibration to reflect the lower positive biopsy rates on rebiopsy.
  
  
  RESULTS
  The full-kallikrein panel had higher discriminative accuracy than PSA and DRE alone, with area under the curve (AUC) improving from 0.58 (95% confidence interval (CI): 0.52, 0.64) to 0.68 (95% CI: 0.62, 0.74), P<0.001, and high-grade cancer (Gleason >or=7) at biopsy with AUC improving from 0.76 (95% CI: 0.64, 0.89) to 0.87 (95% CI: 0.81, 0.94), P=0.003). Application of the panel to 1000 men with persistently elevated PSA after initial negative biopsy, at a 15% risk threshold would reduce the number of biopsies by 712; would miss (or delay) the diagnosis of 53 cancers, of which only 3 would be Gleason 7 and the rest Gleason 6 or less.
  
  
  CONCLUSIONS
  Our data constitute an external validation of a previously published model. The four-kallikrein panel predicts the result of repeat prostate biopsy in men with elevated PSA while dramatically decreasing unnecessary biopsies.
authors.affiliation: Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.forename: M J
authors.initials: MJ
authors.lastname: Roobol
authors.forename: C J
authors.initials: CJ
authors.lastname: Savage
authors.forename: M
authors.initials: M
authors.lastname: Peltola
authors.forename: K
authors.initials: K
authors.lastname: Pettersson
authors.forename: P T
authors.initials: PT
authors.lastname: Scardino
authors.forename: A J
authors.initials: AJ
authors.lastname: Vickers
authors.forename: F H
authors.initials: FH
authors.lastname: Schröder
authors.forename: H
authors.initials: H
authors.lastname: Lilja
mesh_terms: D001706:Biopsy; D055088:Early Detection of Cancer; D006801:Humans; D007610:Kallikreins / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009426:Netherlands; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000175:diagnosis*
chemical_list: D007610:Kallikreins; D017430:Prostate-Specific Antigen