title: Predicting CAP in patients with intermediate PSA using modified PSA indices.
abstract: OBJECTIVE
  To test a new PSA index: peripheral zone fraction PSA (PSA-PZ) and evaluate its' predictive value in patients with intermediate PSA.
  
  
  METHODS
  Fifty seven of 273 patients with serum PSA 4-10 ng/ml had CAP (21%). Total prostate volume and transition zone volume were calculated. Different cut-off points were used to calculate specificity, sensitivity, efficacy, positive and negative predictive values for PSA, PSAD, PSA-TZ and PSA-PZ (PSA-PZ= serum PSA((Total gland volume-TZ volume)/(Total gland volume))
  
  
  RESULTS
  The distribution of PSA-PZ is presented. PSA-PZ is shown to be effective in DRE negative patients with serum PSA 4-10 ng/ml. For patients with PSA-PZ (1.5 ng/ml the biopsy may be spared with no cancer being missed.
  
  
  CONCLUSIONS
  The mathematical formula for PSA-PZ is straightforward and easy to use. Its application is convenient in the clinical setting. We suggest the use of PSA-PZ mainly in DRE negative patients having large glands and serum PSA between 4-10.
authors.affiliation: Urology Department, Assaf-Harofeh Medical Centre, Zerifin, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Zisman
authors.forename: D
authors.initials: D
authors.lastname: Leibovici
authors.forename: J
authors.initials: J
authors.lastname: Kleinmann
authors.forename: Y I
authors.initials: YI
authors.lastname: Siegel
authors.forename: A
authors.initials: A
authors.lastname: Lindner
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001707:Biopsy, Needle; D016009:Chi-Square Distribution; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000032:analysis / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen