AIM: %[-2]proPSA and "prostate health index" (PHI) improve the diagnostic accuracy for clinically relevant prostate cancer at initial and repeat biopsy compared to t-PSA and %f-PSA in men ≤ 65 years old.
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OBJECTIVES: To prospectively test the diagnostic accuracy of %[-2]proPSA and PHI and to determine its role for discrimination between significant and insignificant prostate cancer (PCa) at initial and repeat prostate biopsy in men ≤ 65 years.
PATIENTS AND METHODS: The diagnostic performance of %[-2]proPSA and PHI were evaluated in a multicenter study. A total of 769 men ≤ 65 years old scheduled for initial or repeat prostate biopsy were recruited in four sites based on t-PSA level 1.6-8.0 ng/ml WHO-calibrated (2-10 ng/ml Hybritech-calibrated). Serum samples were measured for the concentration of t-PSA, f-PSA and [-2]proPSA with Beckman Coulter immunoassays on Access-2- or DxI800-instruments. PHI was calculated as ([-2]proPSA/f-PSA) x √t-PSA). Uni- and multivariable logistic regression models and an artificial neural network (ANN) were complemented by decision curve analysis (DCA).
RESULTS: In univariate analysis %[-2]proPSA and PHI were best predictors of PCa detection in all patients (AUC: 0.72 and 0.73), at initial (AUC: 0.67 and 0.69) and repeat biopsy (AUC: 0.74 and 0.74). t-PSA and %f-PSA performed less accurate for all patients (AUC: 0.54 and 0.62). For detection of significant PCa (based on PRIAS-criteria) %[-2]proPSA and PHI equally demonstrated best performance (AUC: 0.70 and 0.73) compared with t-PSA and %f-PSA (AUC: 0.54 and 0.59). In multivariate analysis PHI added to a base model of age, prostate volume, DRE, t-PSA and %f-PSA. PHI was strongest in predicting PCa in all patients, at initial and repeat biopsy and for significant PCa (AUC: 0.73, 0.68, 0.78 and 0.72, respectively). In DCA for all patients the artificial neural network (ANN) showed the broadest threshold probability and best net benefit. PHI as single parameter and the base model + PHI were equivalent with threshold probability and net benefit nearing those of the ANN. For significant cancers the ANN was the strongest parameter in DCA.
CONCLUSION: This multicenter study showed that %[-2]proPSA and PHI have a superior diagnostic performance for detecting PCa in PSA range of 1.6-8.0 ng/ml compared with t-PSA and %f-PSA at initial and repeat biopsy and for predicting significant PCa in men ≤ 65 years old. They are equally superior for counseling patients prior to biopsy.
Boegemann M, Stephan C, Cammann H, Vincendeau S, Houlgatte A, Jung K, Blanchet JS, Semjonow A. Are you the author?
Department of Urology, Prostate Center, University Clinic Muenster, Germany.
Reference: BJU Int. 2015 Mar 28. Epub ahead of print.