title: Serum testosterone improves the accuracy of Prostate Health Index for the detection of prostate cancer.
abstract: OBJECTIVE
  Prostate cancer (PCa) detection suffers from low specificity when using the prostate-specific antigen (PSA) alone. The aim of this study was to investigate the applicability of total testosterone (tT), free testosterone (fT), the fraction (%) of fT to tT (%fT), and bioavailable testosterone (bioT) in serum to improve the diagnostic validity of the serum (-2)pro-PSA-based Prostate Health Index (PHI).
  
  
  METHODS
  Total and free PSA (tPSA, fPSA), (-2)pro-PSA, testosterone, and sex-hormone-binding globulin were measured by automated immunoassays from serum of 193 men scheduled for prostate biopsy (99 PCa, 94 without PCa). fT and bioT were calculated using an online calculator. Statistical analyses were performed by non-parametric tests (Wilcoxon signed rank, Mann-Whitney, Kruskal-Wallis), binary logistic regression, and receiver operating characteristic (ROC) analyses.
  
  
  RESULTS
  Compared with the non-malignant controls, PCa patients had significantly higher tPSA concentrations and PHI values, but lower %fPSA values and lower concentrations of tT, fT, and bioT. PCa could be differentiated from controls by PHI, tT, fT, bioT, and %fPSA. PHI showed the largest area under the ROC curve (AUC=0.73) that was increased further by the inclusion of bioT or tT in a binary logistic regression model. The AUC of PHI in patients with tT concentrations of <8nmol/L (indicating biochemical hypogonadism) was significantly larger than that in patients with higher tT values (0.86 vs. 0.70; P=0.024).
  
  
  CONCLUSIONS
  The PHI-based discrimination between PCa patients and non-malignant controls could be improved by the simultaneous determination of testosterone. Patients with testosterone concentrations of <8nmol/L have the greatest benefit.
authors: Department of Urology, University Hospital Charité, Berlin, Germany. Electronic address: frank.friedersdorff@charite.de.
authors: Frank
authors: F
authors: Friedersdorff
authors: Department of Urology, University Hospital Charité, Berlin, Germany.
authors: Philipp
authors: P
authors: Manus
authors: Department of Urology, University Hospital Charité, Berlin, Germany.
authors: Kurt
authors: K
authors: Miller
authors: Department of Urology, Sana Hospital, Offenbach, Germany.
authors: Michael
authors: M
authors: Lein
authors: Department of Urology, University Hospital Charité, Berlin, Germany; Berlin Institute for Urologic Research, Berlin, Germany.
authors: Klaus
authors: K
authors: Jung
authors: Department of Urology, University Hospital Charité, Berlin, Germany; Berlin Institute for Urologic Research, Berlin, Germany.
authors: Carsten
authors: C
authors: Stephan
mesh_terms: D000368:Aged; D001706:Biopsy; D006801:Humans; D007610:Kallikreins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000378:metabolism* / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Diagnosis; Prostate Health Index; Prostate cancer; Testosterone