title: Correlation and diagnostic performance of the prostate-specific antigen level with the diagnosis, aggressiveness, and bone metastasis of prostate cancer in clinical practice.
abstract: OBJECTIVE
  The common tool for diagnosing prostate cancer is serum prostate-specific antigen (PSA) testing and digital rectal examination, but the disadvantage of the high sensitivity and low specificity of PSA testing in the diagnosis of prostate cancer is a problem in clinical practice. We studied the correlation and diagnostic performance of the PSA level with cancer diagnosis, aggressiveness of prostate cancer (Gleason score>7), and bone metastasis.
  
  
  METHODS
  A total 1,116 patients who underwent transrectal ultrasound and prostate biopsy were retrospectively studied. The patients were divided into subgroups by baseline PSA level as follows: ≤4, 4.1-10, 10.1-20, 20.1-50, 50.1-100, and >100 ng/mL. The area under the receiver operating characteristic curve (AuROC), sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio of each PSA level were evaluated for correlation and diagnostic performance with positive biopsy, Gleason score for aggressiveness, and bone metastasis.
  
  
  RESULTS
  A positive biopsy result was found in 395 patients (35.39%). The PSA level corresponded well with the diagnosis of prostate cancer and a positive bone scan but moderately well with Gleason score as shown by AuROC for diagnosis of prostate cancer (0.82), positive bone scan (0.88), and Gleason score>7 (0.78). The specificity of a PSA level of 4.1-10, 10.1-20, 21.1-50, 50.1-100, and >100 ng/mL in the diagnosis prostate cancer was 9.3, 55.5, 87.5, 98.2, and 99.7, respectively.
  
  
  CONCLUSIONS
  The data showed a strong correlation of PSA level with tumor diagnosis, tumor aggressiveness, and bone metastasis. The prevalence of prostate cancer in this cohort was 35.39%. The chance of diagnosis of prostate cancer was greater than that for benign prostatic hyperplasia when the PSA level was higher than 20 ng/mL.
authors.affiliation: Division of Urology, Department of Surgery, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Bannakij
authors.initials: B
authors.lastname: Lojanapiwat
authors.affiliation: Division of Urology, Department of Surgery, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Wisan
authors.initials: W
authors.lastname: Anutrakulchai
authors.affiliation: Division of Urology, Department of Surgery, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Wilaiwan
authors.initials: W
authors.lastname: Chongruksut
authors.affiliation: Division of Urology, Department of Surgery, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Chaichawan
authors.initials: C
authors.lastname: Udomphot
keywords: Diagnosis; Gleason score; Prostate-specific antigen