title: Reference range for prostate-specific antigen levels after external beam radiation therapy for adenocarcinoma of the prostate.
abstract: OBJECTIVE
  To determine a reference range for prostate-specific antigen (PSA) in patients who have had external beam radiation therapy for adenocarcinoma of the prostate.
  
  
  METHODS
  Serum PSA levels were serially measured with the Hybritech Tandem-R assay in 35 patients who had completed radiation therapy for a mean of 51 +/- 32 months (range, 10 to 133).
  
  
  RESULTS
  Serum PSA levels that were greater than 2.0 ng/mL (n = 20) continued to rise at a rate of more than 1 ng/mL per year, whereas levels between 0.0 and 2.0 ng/mL (n = 15) remained stable for an average of 71 +/- 32 months (range, 22 to 133). One of these latter 15 patients had a false-negative PSA level when he experienced a biopsy-positive prostate nodule and positive bone scan 43 months after therapy.
  
  
  CONCLUSIONS
  Prostate cancer control after radiation therapy was indicated in most men by a PSA reference range of 0.0 to 2.0 ng/mL. Cancer activity was indicated in all men with levels above this range.
authors.forename: R W
authors.initials: RW
authors.lastname: Geist
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000532:radiotherapy*; D012016:Reference Values; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen