title: Utility of percent free prostate-specific antigen in repeat prostate biopsy.
abstract: OBJECTIVE
  To assess the utility of the percent free prostate-specific antigen (%fPSA) for the prediction of prostate cancer in men undergoing repeat biopsy.
  
  
  METHODS
  A retrospective review was performed of 1037 patients in an institutional review board-approved repeat prostate biopsy database. A total of 617 patients who underwent 683 biopsies had all their data available for analysis. The patients were categorized as having undergone 1 repeat biopsy or >1 repeat biopsy.
  
  
  RESULTS
  The overall cancer detection rate was 27% and 22% in men who underwent 1 and >1 repeat biopsy, respectively. The area under the receiver operating characteristic curve for the %fPSA was 0.65 for men who underwent 1 repeat biopsy. Multivariate analysis demonstrated that a positive family history, decreasing %fPSA, and presence of high-grade intraepithelial neoplasia and/or atypical small acinar proliferation predicted for cancer. The univariate odds ratio for every 5% decrease in the %fPSA was 1.5 (95% confidence interval 1.2-1.7). The performance of %fPSA was further improved in men who underwent >1 repeat biopsy, with an area under the curve of 0.72. In men who underwent >1 repeat biopsy, multivariate analysis showed that a decreasing %fPSA, >20 cores removed, and high-grade intraepithelial neoplasia predicted for cancer. The univariate odds ratio for every 5% decrease in the %fPSA was 1.8 (95% confidence interval 1.4-2.3). A %fPSA cutoff of 10% achieved 90% and 91% specificity in the 1 repeat biopsy and >1 repeat biopsy groups, respectively.
  
  
  CONCLUSIONS
  %fPSA is useful in predicting for prostate cancer in the repeat biopsy population, particularly for those who have undergone multiple repeat biopsies. A persistently low %fPSA should prompt additional investigation in these men.
authors.affiliation: Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Byron H
authors.initials: BH
authors.lastname: Lee
authors.forename: Adrian V
authors.initials: AV
authors.lastname: Hernandez
authors.forename: Osama
authors.initials: O
authors.lastname: Zaytoun
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Berglund
authors.forename: Michael C
authors.initials: MC
authors.lastname: Gong
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Jones
mesh_terms: D000368:Aged; D001706:Biopsy / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology*; D012189:Retrospective Studies
chemical_list: D017430:Prostate-Specific Antigen