title: Can complexed prostate specific antigen enhance prostate cancer detection in Japanese men?
abstract: BACKGROUND
  The aim of this study is to ascertain whether Bayer complexed PSA (cPSA) and volume referenced cPSA could enhance the detection of prostate cancer in Japanese men.
  
  
  METHODS
  A total of 214 Japanese men whose serum total PSA (tPSA) values ranged from 1.2 ng/ml to 4600 ng/ml were enrolled from two institutions. Serum samples for tPSA, free PSA, PSA-alpha-1-antichymotripsin (PSA-ACT) and cPSA (ADVIA-Centaur) were obtained in all cases. In addition, total gland (TGV) as well as transition zone volume (TZV) were determined in all cases who underwent untrasound guided prostate biopsy (sextant and two additional transition zone biopsies). Biopsy outcome was correlated to the following parameters: tPSA, cPSA, PSA-ACT, free to total (F/T) PSA ratio, 2 complex to total (C/T) PSA ratios and 6 volume referenced parameters.
  
  
  RESULTS
  Prostate cancer was detected in 85 of 214 patients (40%). The area under the receiver operating characteristic curve in non-volume referenced variables was highest for cPSA (0.736), followed by PSA-ACT (0.735), tPSA (0.722), F/T PSA ratio (0.613) and C/T PSA ratio (0.591). Comparing tPSA with the cutoff value of 4.0 ng/ml, the cutoff value with a 2.8 ng/ml of cPSA detected one more positive biopsy patient, decreasing one more cancer missed case and 8 more false positive cases. At sensitivities of 85% to 95% in men with tPSA between 4.00 and 10.00 ng/ml (n = 116), there were no significant differences in the corresponding specificities between tPSA and cPSA, or between cPSA and PSA-ACT. At sensitivities of 90% to 95%, the corresponding specificities of PSA-ACT adjusted for transition zone volume revealed best performance. As for the performance in men with a tPSA less than 4.0 ng/ml, the specificities of cPSA performed best, and differed significantly from PSA-ACT and F/T PSA at sensitivities of 80% to 90%.
  
  
  CONCLUSIONS
  Bayer cPSA could replace the first screening test by total PSA and can enhance cancer detection, compared with PSA-ACT. However, cPSA did not provide additional value in differentiating cancer from non-cancer cases in men with a tPSA between 4.00 and 10.00 ng/ml.
authors.affiliation: Department of Urology, Kyoto Prefectural University of Medicine, Kawaramachi Hirokoji, Kyoto 602-8566, Japan. okiharakoji@hotmail.com
authors.forename: Koji
authors.initials: K
authors.lastname: Okihara
authors.forename: Osamu
authors.initials: O
authors.lastname: Ukimura
authors.forename: Terukazu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Mizutani
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kawauchi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Naya
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Uchida
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogiwara
authors.forename: Tsuneharu
authors.initials: T
authors.lastname: Miki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen