title: Ability of serum prostate-specific antigen levels to predict normal bone scans in patients with newly diagnosed prostate cancer.
abstract: OBJECTIVE
  To determine whether pretreatment serum prostate-specific antigen (PSA) levels in newly diagnosed prostate cancer patients can identify a group with a low probability of osseous metastasis and safely eliminate the need for a bone scan as a routine part of the staging evaluation.
  
  
  METHODS
  We retrospectively reviewed 683 patients with prostate cancer between 1990 and 1993. Patients with prior therapy or serum PSA levels obtained longer than 3 months prior to bone scan were excluded. Bone scans were reviewed by two nuclear medicine physicians with a third deciding equivocal cases.
  
  
  RESULTS
  Only 6% of 490 evaluable patients had a positive bone scan on initial evaluation. Scans were positive in 0 of 290 (0%) with PSA levels below 10 micrograms/L, 4 of 88 (4.5%) with PSA levels between 10 and 20 micrograms/L, and 24 of 112 (21%) with PSA levels above 20 micrograms/L. Although the risk of a positive bone scan increased with increasing PSA levels, PSA is a poor positive predictor of positive bone scans. The risk of a positive bone scan was 8% (5 of 64 patients) when PSA was between 20 and 50 micrograms/L, and increased to 40% (19 of 48 patients) for PSA levels greater than 50 micrograms/L. In contrast, serum PSA levels below 10 micrograms/L are strong negative predictors of positive bone scans, with no positive scans in 290 patients with PSA levels below 10 micrograms/L. Although the risk of a positive bone scan increased with increasing stage and grade, tumor stage and grade were poor negative predictors of positive bone scans. Up to 4% of patients with clinically confined or well-differentiated to moderately differentiated tumors had positive scans. Scans were positive in 12% of poorly differentiated tumors, but all these patients had PSA levels above 10 micrograms/L.
  
  
  CONCLUSIONS
  Our data support the elimination of routine bone scintigraphy in patients with newly diagnosed prostate cancer and PSA levels below 10 micrograms/L. Bone scans are indicated when PSA levels are above 10 micrograms/L, or with T3 or poorly differentiated disease.
authors.affiliation: Department of Surgery and Radiology, University of British Columbia, Vancouver Hospital and Health Sciences Centre, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Gleave
authors.forename: D
authors.initials: D
authors.lastname: Coupland
authors.forename: D
authors.initials: D
authors.lastname: Drachenberg
authors.forename: L
authors.initials: L
authors.lastname: Cohen
authors.forename: S
authors.initials: S
authors.lastname: Kwong
authors.forename: S L
authors.initials: SL
authors.lastname: Goldenberg
authors.forename: L D
authors.initials: LD
authors.lastname: Sullivan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging / Q000556:secondary; D006801:Humans; 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; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D017430:Prostate-Specific Antigen