title: Prostate cancer detection in men with a 'normal' total prostate-specific antigen (PSA) level using percentage free PSA: a prospective screening study.
abstract: OBJECTIVE
  To assess the utility of percentage free/total prostate-specific antigen (f/tPSA) levels for detecting prostate cancer in a prospectively screened population of men with a 'normal' total PSA level.
  
  
  METHODS
  Men aged 50-65 years were contacted via their general practitioner and invited for prostate cancer screening. All had their total and f/tPSA levels measured; those meeting the biopsy criteria (PSA 1.1-3.99 ng/mL and f/tPSA < or = 20%) were offered a biopsy. The cancer detection rate was then evaluated and compared with other methods of detection. In all, 773 men were screened, of whom 115 met the criteria and agreed to undergo a prostate biopsy.
  
  
  RESULTS
  Cancer was detected in 13 of the 115 men (11.3%) of whom most would have been missed by lowering the age-adjusted threshold for total PSA to 2.5 ng/mL. There was no significant difference in total and f/tPSA values in men with and without prostate cancer. Those cancers that could be evaluated were found to be clinically significant.
  
  
  CONCLUSIONS
  In this study prostate cancer was detected solely on the basis of a low f/tPSA value. Most men with cancer would have been missed by simply lowering the age-adjusted threshold for total PSA. Using the f/tPSA level may allow the detection of clinically significant cancer in men at a time when they are most likely to benefit from treatment.
authors.affiliation: Department of Urology, St Mary's Hospital, London, UK. Ed.rowe@ukgateway.net
authors.forename: Edward W J
authors.initials: EW
authors.lastname: Rowe
authors.forename: Mark E
authors.initials: ME
authors.lastname: Laniado
authors.forename: Marjorie M
authors.initials: MM
authors.lastname: Walker
authors.forename: Anup
authors.initials: A
authors.lastname: Patel
mesh_terms: D000368:Aged; D001706:Biopsy / Q000379:methods; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D017430:Prostate-Specific Antigen