title: Evaluation of the serum testosterone to prostate-specific antigen ratio as a predictor of prostate cancer risk.
abstract: OBJECTIVE
  To analyse the ratio of serum testosterone (sT) to prostate-specific antigen (PSA) as a predictor of prostate cancer risk, as low levels of sT have been related to a greater risk of prostate cancer, and its ratio with serum PSA level was recently proposed as a new tool to increase the specificity of PSA.
  
  
  METHODS
  In all, 439 consecutive men with a normal digital rectal examination and a serum PSA level of 4.1-20 ng/mL had a transrectal ultrasonography-guided biopsy using a 10-core scheme, with an additional 1-8 cores according to prostate volume and patient age. The sT level was determined before the procedure using a chemiluminescent assay, and the ratio of sT to PSA (sT/PSA) was calculated after transforming sT measurements from ng/dL to ng/mL. The percentage free PSA (%fPSA) and PSA density were also included in this analysis.
  
  
  RESULTS
  The overall cancer detection rate was 42.1%. The median sT level was 469 ng/dL in men with cancer and 499 ng/dL in those without (P = 0.521). The median sT/PSA was 0.68 and 0.74, respectively (P = 0.215). However, the median %fPSA was 14 in men with cancer and 17 in men without (P < 0.001) and the median PSA density was 0.22 and 0.16, respectively (P < 0.001). The multivariate analysis confirmed the independent predictive value only for %fPSA (odds ratio 0.94, 95% confidence interval 0.91-0.98) and PSA density (5.8, 3.42-19.8).
  
  
  CONCLUSIONS
  These results do not support the use of sT/PSA for predicting the risk of prostate cancer and to increase the specificity of PSA.
authors.affiliation: Department of Urology, Vall d'Hebron Hospital, Autonoma University of Barcelona, Spain. jmorote@vhebron.net
authors.forename: Juan
authors.initials: J
authors.lastname: Morote
authors.forename: Jacques
authors.initials: J
authors.lastname: Planas
authors.forename: Cristobal
authors.initials: C
authors.lastname: Ramirez
authors.forename: Esther
authors.initials: E
authors.lastname: Gómez
authors.forename: Carles X
authors.initials: CX
authors.lastname: Raventós
authors.forename: José
authors.initials: J
authors.lastname: Placer
authors.forename: Roberto
authors.initials: R
authors.lastname: Catalán
authors.forename: Inés M
authors.initials: IM
authors.lastname: de Torres
mesh_terms: D000368:Aged; D004812:Epidemiologic Methods; D006801:Humans; D007006:Hypogonadism / Q000097:blood / Q000150:complications; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D017430:Prostate-Specific Antigen