title: Serial Percent Free Prostate Specific Antigen in Combination with Prostate Specific Antigen for Population Based Early Detection of Prostate Cancer.
abstract: We characterized the diagnostic properties of serial percent free prostate specific antigen in relation to prostate specific antigen in a multiethnic, multiracial cohort of healthy men.
  
  
  
  A total of 6,982 percent free prostate specific antigen and prostate specific antigen measurements were obtained from participants in a greater than 12-year Texas screening study comprising 1,625 men who never underwent biopsy, 497 who underwent 1 or more biopsies negative for prostate cancer and 61 diagnosed with prostate cancer. We evaluated the ROC AUC of percent free prostate specific antigen and the proportion of patients with fluctuating values across multiple visits determined according to 2 thresholds (less than 15% vs 25%). The proportion of cancer cases in which percent free prostate specific antigen indicated a positive test before prostate specific antigen greater than 4 ng/ml did and the number of negative biopsies that would have been spared by negative percent free prostate specific antigen test results were calculated.
  
  
  
  Percent free prostate specific antigen fluctuated around its threshold of less than 25% (less than 15%) in 38.3% (78.1%), 42.2% (20.9%), and 11.4% (25.7%) of patients never biopsied, and with negative and positive biopsies, respectively. At the same thresholds, percent free prostate specific antigen tested positive earlier than prostate specific antigen in 71.4% and 34.2% of cancer cases, respectively. Among men with multiple negative biopsies and PSA greater than 4 ng/ml, percent free PSA would have tested negative in 31.6% and 65.8%, respectively.
  
  
  
  Percent free prostate specific antigen should accompany prostate specific antigen testing to potentially spare unnecessary biopsies or detect cancer earlier. When near the threshold, both tests should be repeated due to commonly observed fluctuation.
authors.affiliation: Department of Epidemiology and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, Texas; Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas; Department of Mathematics, Technische Universitaet Muenchen, Munich, Germany. Electronic address: ankerst@tum.de.
authors.forename: Donna Pauler
authors.initials: DP
authors.lastname: Ankerst
authors.affiliation: Department of Epidemiology and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Gelfond
authors.affiliation: Department of Epidemiology and Biostatistics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Martin
authors.initials: M
authors.lastname: Goros
authors.affiliation: Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Jesus
authors.initials: J
authors.lastname: Herrera
authors.affiliation: Department of Mathematics, Technische Universitaet Muenchen, Munich, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Strobl
authors.affiliation: Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Thompson
authors.affiliation: Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Javier
authors.initials: J
authors.lastname: Hernandez
authors.affiliation: Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Leach
mesh_terms: D019540:Area Under Curve; D055088:Early Detection of Cancer / Q000379:methods*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D012372:ROC Curve
chemical_list: D017430:Prostate-Specific Antigen
keywords: biopsy; diagnosis; mass screening; prostate-specific antigen; prostatic neoplasms