title: Free and complexed prostate-specific antigen serum ratios to predict probability of primary prostate cancer and benign prostatic hyperplasia.
abstract: OBJECTIVE
  Ratios of free to total prostate-specific antigen (f/t PSA ratio) improved differentiation of benign prostatic hyperplasia (BPH) from prostate cancer (CaP). Using sera obtained at least 1 month prior to biopsy-confirmed diagnosis and logistic regression adjusted for disease prevalence, probability curves are constructed to predict the presence of CaP.
  
  
  METHODS
  The patient population included 122 (44%) BPH sera and 155 (56%) prostate carcinoma sera collected prior to any therapy. The total PSA range = 2.0-20.0 ng/mL; median age = 69 years. External reference standards for both free and total PSA assays were used to standardize the assays and correct the ratio. Probability curves and tables for cancer incidence were formulated for a subset of the total test population (total PSA range = 2.0-10.0 ng/mL; 98 BPH, 118 CaP patients) by using logistic regression and prior cancer prevalence statistics derived from a published patient screening study.
  
  
  RESULTS
  Median f/t PSA ratios were 0.18 and 0.12 in the overall sample and 0.19 and 0.12 in the subset for BPH and CaP, respectively (P = 0.0001). The median total PSA concentrations for BPH and CaP were 5.8 and 6.7 ng/mL when total PSA range = 2.0-20.0 ng/mL and were 4.9 and 5.9 ng/mL when total PSA range = 2.0-10.0, respectively.
  
  
  CONCLUSIONS
  Cancer probability curves were constructed to help guide decisions concerning biopsy and other aspects of prostate cancer disease management. Further validation of this approach in another series of patients is necessary and is planned.
authors.affiliation: UroCor, Inc., UroSciences Group, Ohlahoma City, Oklahoma 73104-3699, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Marley
authors.forename: M C
authors.initials: MC
authors.lastname: Miller
authors.forename: M W
authors.initials: MW
authors.lastname: Kattan
authors.forename: G
authors.initials: G
authors.lastname: Zhao
authors.forename: K P
authors.initials: KP
authors.lastname: Patton
authors.forename: R L
authors.initials: RL
authors.lastname: Vessella
authors.forename: G L
authors.initials: GL
authors.lastname: Wright
authors.forename: P F
authors.initials: PF
authors.lastname: Schellhammer
authors.forename: R W
authors.initials: RW
authors.lastname: Veltri
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood / Q000175:diagnosis*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D017430:Prostate-Specific Antigen