title: Use of percentage of free prostate-specific antigen to identify men at high risk of prostate cancer when PSA levels are 2.51 to 4 ng/mL and digital rectal examination is not suspicious for prostate cancer: an alternative model.
abstract: OBJECTIVE
  Currently, many clinicians do not recommend prostate biopsy for men with digital rectal examination (DRE) results that are not suspicious for cancer and prostate-specific antigen (PSA) values between 2.51 and 4 ng/mL. We propose a new model for the detection of prostate cancer using the percentage of free PSA (%FPSA) in the limited range of PSA values between 2.51 and 4 ng/mL that maximizes clinical specificity (ie, minimizes false-positive results). This model identifies higher risk patients in this relatively low-risk population.
  
  
  METHODS
  Three hundred sixty-eight archived serum samples from men evaluated and treated at two academic institutions were reviewed. All men had a histologic diagnosis, findings not suspicious for cancer on DRE, and PSA levels between 2.51 and 4 ng/mL. Samples were tested in Hybritech's Tandem-R PSA and Tandem-R free PSA (FPSA) assays in the same laboratory at each institution.
  
  
  RESULTS
  Various models for cancer detection using %FPSA when PSA is 2.51 to 4 ng/mL and DRE is not suspicious for cancer are proposed. These models recommend biopsy for only 10% to 36% of the men in this population and would identify as many as 30% to 54% of the detectable cancers. There is evidence that the cancers that would be detected are the most aggressive cancers in this population.
  
  
  CONCLUSIONS
  Our models identified men with a higher risk of prostate cancer in a relatively low-risk population that currently does not routinely undergo biopsy. This may allow for a more cost-effective way to increase cancer detection when PSA values are between 2.51 and 4 ng/mL and DRE is not suspicious for cancer. This model has the potential to detect a greater number of clinically important and potentially curable cancers than would be detected with current practice.
authors.affiliation: Division of Urologic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Catalona
authors.forename: A W
authors.initials: AW
authors.lastname: Partin
authors.forename: J A
authors.initials: JA
authors.lastname: Finlay
authors.forename: D W
authors.initials: DW
authors.lastname: Chan
authors.forename: H G
authors.initials: HG
authors.lastname: Rittenhouse
authors.forename: R L
authors.initials: RL
authors.lastname: Wolfert
authors.forename: D L
authors.initials: DL
authors.lastname: Woodrum
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D008875:Middle Aged; D010173:Palpation; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D012007:Rectum; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D017430:Prostate-Specific Antigen