title: A panel of kallikrein markers can predict outcome of prostate biopsy following clinical work-up: an independent validation study from the European Randomized Study of Prostate Cancer screening, France.
abstract: BACKGROUND
  We have previously shown that a panel of kallikrein markers--total prostate-specific antigen (PSA), free PSA, intact PSA and human kallikrein-related peptidase 2 (hK2)--can predict the outcome of prostate biopsy in men with elevated PSA. Here we investigate the properties of our panel in men subject to clinical work-up before biopsy.
  
  
  METHODS
  We applied a previously published predictive model based on the kallikrein panel to 262 men undergoing prostate biopsy following an elevated PSA (≥ 3 ng/ml) and further clinical work-up during the European Randomized Study of Prostate Cancer screening, France. The predictive accuracy of the model was compared to a "base" model of PSA, age and digital rectal exam (DRE).
  
  
  RESULTS
  83 (32%) men had prostate cancer on biopsy of whom 45 (54%) had high grade disease (Gleason score 7 or higher). Our model had significantly higher accuracy than the base model in predicting cancer (area-under-the-curve [AUC] improved from 0.63 to 0.78) or high-grade cancer (AUC increased from 0.77 to 0.87). Using a decision rule to biopsy those with a 20% or higher risk of cancer from the model would reduce the number of biopsies by nearly half. For every 1000 men with elevated PSA and clinical indication for biopsy, the model would recommend against biopsy in 61 men with cancer, the majority (≈80%) of whom would have low stage and low grade disease at diagnosis.
  
  
  CONCLUSIONS
  In this independent validation study, the model was highly predictive of prostate cancer in men for whom the decision to biopsy is based on both elevated PSA and clinical work-up. Use of this model would reduce a large number of biopsies while missing few cancers.
authors.affiliation: Hôpital Bichat-Claude Bernard, Paris, France.
authors.forename: Amine
authors.initials: A
authors.lastname: Benchikh
authors.forename: Caroline
authors.initials: C
authors.lastname: Savage
authors.forename: Angel
authors.initials: A
authors.lastname: Cronin
authors.forename: Gilles
authors.initials: G
authors.lastname: Salama
authors.forename: Arnauld
authors.initials: A
authors.lastname: Villers
authors.forename: Hans
authors.initials: H
authors.lastname: Lilja
authors.forename: Andrew
authors.initials: A
authors.lastname: Vickers
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001706:Biopsy; D055088:Early Detection of Cancer / Q000379:methods; D005060:Europe; D005602:France; D006801:Humans; D007610:Kallikreins / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D017430:Prostate-Specific Antigen / Q000096:biosynthesis; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D015203:Reproducibility of Results; D016896:Treatment Outcome
chemical_list: D007610:Kallikreins; D017430:Prostate-Specific Antigen