title: Percentage of free PSA in black versus white men for detection and staging of prostate cancer: a prospective multicenter clinical trial.
abstract: OBJECTIVE
  In predominately white populations, measurement of the percentage of free prostate-specific antigen (%fPSA) has been shown to enhance the specificity of total PSA testing for prostate cancer while maintaining high sensitivity and to aid in prostate cancer staging. This study evaluated whether the %fPSA cutoff that maintained a 95% sensitivity in a white population yielded the same sensitivity and specificity in a black population and whether %fPSA was useful in predicting postoperative pathologic features in blacks.
  
  
  METHODS
  We evaluated 647 white and 79 black men, prospectively enrolled at prostate cancer screening and surgical referral centers. Subjects were 50 to 75 years old with digital rectal examination findings that were not suspicious for prostate cancer and total PSA values between 4.0 and 10.0 ng/mL. All had undergone needle biopsy of the prostate. Hybritech's Tandem total and free PSA assays were used.
  
  
  RESULTS
  Ninety-five percent sensitivity was attained with a %fPSA cutoff of 25% in both races. Use of this cutoff could have avoided unnecessary biopsies in 20% of white and 17% of black subjects (P = 0.69). In receiver operating characteristic (ROC) curve analysis, the area under the curve (AUC) for %fPSA was significantly higher than for total PSA in both blacks (0.76 versus 0.56, P <0.01) and whites (0.70 versus 0.54, P <0.001). In both races, higher %fPSA values indicated a lower risk of cancer and also predicted favorable pathologic features in radical prostatectomy specimens.
  
  
  CONCLUSIONS
  A 25% fPSA cutoff detected 95% of cancers and reduced unnecessary biopsies in both races. Higher %fPSA values were associated with favorable postoperative histopathologic findings in both races.
authors.affiliation: Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Catalona
authors.forename: A W
authors.initials: AW
authors.lastname: Partin
authors.forename: K M
authors.initials: KM
authors.lastname: Slawin
authors.forename: C K
authors.initials: CK
authors.lastname: Naughton
authors.forename: M K
authors.initials: MK
authors.lastname: Brawer
authors.forename: R C
authors.initials: RC
authors.lastname: Flanigan
authors.forename: J P
authors.initials: JP
authors.lastname: Richie
authors.forename: A
authors.initials: A
authors.lastname: Patel
authors.forename: P C
authors.initials: PC
authors.lastname: Walsh
authors.forename: P T
authors.initials: PT
authors.lastname: Scardino
authors.forename: P H
authors.initials: PH
authors.lastname: Lange
authors.forename: J B
authors.initials: JB
authors.lastname: deKernion
authors.forename: P C
authors.initials: PC
authors.lastname: Southwick
authors.forename: K G
authors.initials: KG
authors.lastname: Loveland
authors.forename: R E
authors.initials: RE
authors.lastname: Parson
authors.forename: G H
authors.initials: GH
authors.lastname: Gasior
mesh_terms: D000368:Aged; D019540:Area Under Curve; D001706:Biopsy; D044383:Black People; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000208:ethnology / Q000473:pathology / Q000601:surgery; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D044465:White People
chemical_list: D017430:Prostate-Specific Antigen