title: Complexed prostate-specific antigen for the diagnosis of biochemical recurrence after radical prostatectomy.
abstract: OBJECTIVE
  To determine the validity of using complexed prostate-specific antigen (cPSA) levels for diagnosing biochemical recurrence after radical prostatectomy (RP).
  
  
  METHODS
  With linear regression modelling, we determined threshold cPSA levels for biochemical recurrence in patients after RP for clinically localized prostate cancer. We calculated sensitivity, specificity, predictive values, and likelihood ratio tests of each threshold for diagnosing biochemical recurrence using total PSA (tPSA) as the reference standard.
  
  
  RESULTS
  In the regression models, tPSA and cPSA were highly correlated (r = 0.99). For the diagnosis of biochemical recurrence, tPSA thresholds of 0.20 and 0.40 ng/mL corresponded to cPSA thresholds of 0.12 ng/mL (95% confidence interval 0.08-0.17) and 0.29 (0.22-0.28) ng/mL, respectively. For the detection of biochemical recurrence, a cPSA threshold of 0.12 ng/mL had a sensitivity of 96%, specificity of 88%, positive predictive value of 89%, negative predictive value of 88%, positive likelihood ratio of 8, and negative likelihood ratio of 0.05; the respective values for a cPSA threshold of 0.29 ng/mL were 96%, 96%, 96%, 96%, 24 and 0.04.
  
  
  CONCLUSIONS
  cPSA has high validity for the diagnosis of biochemical recurrence after RP. Pending external validation, cPSA might be useful for biochemical surveillance after RP.
authors: James Buchanan Brady Urological Institute, The Johns Hopkins Medical Institution, Baltimore, MD, USA. jkparsons@ucsd.edu
authors: J Kellogg
authors: JK
authors: Parsons
authors: Alan W
authors: AW
authors: Partin
authors: Bruce
authors: B
authors: Trock
authors: Debra J
authors: DJ
authors: Bruzek
authors: Carol
authors: C
authors: Cheli
authors: Lori J
authors: LJ
authors: Sokoll
mesh_terms: D015331:Cohort Studies; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000378:metabolism*; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000601:surgery; D012044:Regression Analysis; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen