title: Serum free prostate specific antigen and prostate specific antigen density measurements for predicting cancer in men with prior negative prostatic biopsies.
abstract: OBJECTIVE
  We examined the usefulness of measurements of free prostate specific antigen (PSA) and PSA density for predicting prostate cancer in men who had had a prior negative biopsy, a serum PSA level of 4.1 to 10.0 ng./ml. and benign findings on prostate examination.
  
  
  METHODS
  We measured percent free serum PSA and PSA density in 163 male volunteers age 50 years or older who were advised to have repeat prostatic biopsies for a serum PSA level of 4.1 to 10.0 ng./ml.
  
  
  RESULTS
  Of 99 men who had repeat biopsies 20 (20%) had prostate cancer detected. Prostate cancer was significantly associated with lower free PSA level and higher PSA density, with overlap in 83% of the cases. The use of percent free PSA cutoffs of 28 and 30% would have detected 90 and 95% of cancers, respectively, and avoided 13 and 12% of the biopsies, respectively. PSA density cutoffs of 0.10 and 0.08 would have detected 90 and 95% of cancers, respectively, and avoided 31 and 12% of biopsies, respectively.
  
  
  CONCLUSIONS
  Free PSA and PSA density predict prostate cancer in men who have had prior negative prostatic biopsies, serum PSA levels of 4.1 to 10.0 ng./ml. and a benign prostate examination. Both parameters may be used to avoid unnecessary biopsies with an acceptable decrease in sensitivity. Further studies are needed to determine cutoffs to be used in clinical practice.
authors.affiliation: 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: J A
authors.initials: JA
authors.lastname: Beiser
authors.forename: D S
authors.initials: DS
authors.lastname: Smith
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005188:False Negative Reactions; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology*; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen