title: Can one blood draw replace transrectal ultrasonography-estimated prostate volume to predict prostate cancer risk?
abstract: OBJECTIVE
  To explore whether a panel of kallikrein markers in blood: total, free and intact prostate-specific antigen (PSA) and kallikrein-related peptidase 2, could be used as a non-invasive alternative for predicting prostate cancer on biopsy in a screening setting.
  
  
  METHODS
  The study cohort comprised previously unscreened men who underwent sextant biopsy owing to elevated PSA (≥3 ng/mL) in two different centres of the European Randomized Study of Screening for Prostate Cancer, Rotterdam (n = 2914) and Göteborg (n = 740). A statistical model, based on kallikrein markers, was compared with one based on established clinical factors for the prediction of biopsy outcome.
  
  
  RESULTS
  The clinical tests were found to be no better than blood markers, with an area under the curve in favour of the blood measurements of 0.766 vs. 0.763 in Rotterdam and 0.809 vs. 0.774 in Göteborg. Adding digital rectal examination (DRE) or DRE plus transrectal ultrasonography (TRUS) volume to the markers improved discrimination, although the increases were small. Results were similar for predicting high-grade cancer. There was a strong correlation between the blood measurements and TRUS-estimated prostate volume (Spearman's correlation 0.60 in Rotterdam and 0.57 in Göteborg).
  
  
  CONCLUSIONS
  In previously unscreened men, each with indication for biopsy, a statistical model based on kallikrein levels was similar to a clinical model in predicting prostate cancer in a screening setting, outside the day-to-day clinical practice. Whether a clinical approach can be replaced by laboratory analyses or used in combination with decision models (nomograms) is a clinical judgment that may vary from clinician to clinician depending on how they weigh the different advantages and disadvantages (harms, costs, time, invasiveness) of both approaches.
authors: Department of Surgery (Urology Service), Memorial Sloan-Kettering Cancer Center, New York, USA; Department of Urology, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg.
authors: Sigrid V
authors: SV
authors: Carlsson
authors: Mari T
authors: MT
authors: Peltola
authors: Daniel
authors: D
authors: Sjoberg
authors: Fritz H
authors: FH
authors: Schröder
authors: Jonas
authors: J
authors: Hugosson
authors: Kim
authors: K
authors: Pettersson
authors: Peter T
authors: PT
authors: Scardino
authors: Andrew J
authors: AJ
authors: Vickers
authors: Hans
authors: H
authors: Lilja
authors: Monique J
authors: MJ
authors: Roobol
mesh_terms: D000368:Aged; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000097:blood*; D051517:Digital Rectal Examination / Q000379:methods*; D055088:Early Detection of Cancer / Q000379:methods* / Q000639:trends; D006801:Humans; D007610:Kallikreins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D009929:Organ Size; D010808:Physical Examination; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging / Q000473:pathology; D013548:Sweden; D014463:Ultrasonography
chemical_list: D014408:Biomarkers, Tumor; D007610:Kallikreins
keywords: kallikreins; prostate cancer; prostate-specific antigen; transrectal ultrasonography