title: The outcomes of transrectal ultrasound guided biopsy of the prostate in a New Zealand population.
abstract: BACKGROUND
  We aim to produce nomograms relating age, digital rectal examinations (DRE), and prostate specific antigen (PSA) to probability of a positive transrectal ultrasound guided (TRUS) prostate biopsy for a New Zealand population. Usefulness of age-adjusted PSA reference ranges and PSA density are also examined.
  
  
  METHODS
  Data was extracted retrospectively from electronic records of prostate biopsies performed between 1995-2007 in Christchurch, New Zealand. Nomograms were created using logistic regression models. The area under the curve (AUC) for age-adjusted PSA ranges, PSA density, and PSA in predicting a positive biopsy was calculated and used to compare these methods.
  
  
  RESULTS
  4316 biopsies were available for analysis. Data was incomplete for 1177 (27%) of patients. Biopsy was positive in 54.4%. PSA level and DRE finding were strong predictors of a malignant biopsy in our multivariable model but age was not. PSA level and DRE were also predictors of a higher Gleason score (7 or greater). Nomograms are presented relating PSA and DRE to both a positive biopsy result and to biopsy with Gleason score 7 or greater. AUC for age adjusted reference ranges was no better than PSA using a single cutpoint of 4.0. (0.54 vs 0.53). AUC for PSA density using a cutpoint of 0.15 was 0.72. Receiver Operator Characteristic (ROC) curves showed a clear advantage for PSA density over PSA regardless of cutpoint. (AUC 0.80 vs 0.67).
  
  
  CONCLUSIONS
  Nomograms are formulated to help inform New Zealand men how likely they are to have a positive TRUS prostate biopsy and also how likely they are to have a higher grade cancer detected by TRUS prostate biopsy. Age-adjusted reference ranges did not improve prediction of cancer in this population, but the use of PSA density may enhance prostate cancer diagnosis.
authors.affiliation: Department of Urology, Canterbury District Health Board, Christchurch, New Zealand.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lienert
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Davidson
authors.forename: J Elisabeth
authors.initials: JE
authors.lastname: Wells
mesh_terms: D000367:Age Factors; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D001706:Biopsy; D051517:Digital Rectal Examination; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D049451:Nomograms; D011237:Predictive Value of Tests; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis*; D012372:ROC Curve; D012189:Retrospective Studies; D014463:Ultrasonography
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen