title: Urinary thiosulfate as failed prostate cancer biomarker - an exemplary multicenter re-evaluation study.
abstract: BACKGROUND
  In 2013, thiosulfate in urine has been proposed as promising prostate cancer (PCa) biomarker. However, a missing comparison with other proven PCa markers suggested a re-evaluation study. Therefore, together with the authors from the initial study, the diagnostic accuracy of thiosulfate was compared with that of urinary prostate cancer associated 3 (PCA3), serum prostate health index (Phi), and percent free prostate-specific antigen (%fPSA). Thiosulfate was further measured in a multicenter approach to exclude center-related biases.
  
  
  METHODS
  Thiosulfate, calculated as ratio of thiosulfate to urinary creatinine (TS/Crea ratio), was measured in two cohorts in a total of 269 patients. In the retrospective study (n=160) PCA3, Phi, PSA, and %fPSA were compared with the TS/Crea ratio between patients with and without PCa according to the prostate needle biopsy results. The second prospective cohort included 109 patients from four centers.
  
  
  RESULTS
  The median TS/Crea ratio was not statistically different between the patients with and without PCa. The receiver-operating characteristics showed that the TS/Crea ratio was unable to discriminate between patients with and without PCa in contrast to %fPSA, Phi, and PCA3. In all four centers, the low median TS/Crea ratios (<1 mmol/mol) in both patient cohorts were confirmed and thiosulfate was again not able to distinguish between them (p-values, 0.13-0.90).
  
  
  CONCLUSIONS
  This study could not confirm the previously observed high median TS/Crea ratio in PCa patients in comparison to non-PCa patients. Thiosulfate subsequently failed as PCa biomarker while PCA3 and Phi showed the expected diagnostic improvement.
authors.forename: Carsten
authors.initials: C
authors.lastname: Stephan
authors.forename: Jacek
authors.initials: J
authors.lastname: Wilkosz
authors.forename: Waldemar
authors.initials: W
authors.lastname: Różański
authors.forename: Thorsten H
authors.initials: TH
authors.lastname: Ecke
authors.forename: Michael
authors.initials: M
authors.lastname: Lein
authors.forename: Magdalena
authors.initials: M
authors.lastname: Bryś
authors.forename: Anna
authors.initials: A
authors.lastname: Krześlak
authors.forename: Grażyna
authors.initials: G
authors.lastname: Chwatko
authors.forename: Klaus
authors.initials: K
authors.lastname: Jung
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000652:urine*; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000652:urine*; D013885:Thiosulfates / Q000652:urine*
chemical_list: D014408:Biomarkers, Tumor; D013885:Thiosulfates