Background: Total prostate-specific antigen (tPSA) is flawed for prostate cancer (PCa) detection. [-2]proprostate-specific antigen (p2PSA), a molecular isoform of free PSA (fPSA), shows higher specificity compared with tPSA or percentage of free PSA (%fPSA). The prostate health index (Phi), a measure based on p2PSA and calculated as p2PSA/fPSA × √tPSA, was evaluated in a multicenter study for detecting PCa.
Methods: A total of 1362 patients from 4 different study sites who had tPSA values of 1.6-8.0 μg/L (668 patients with PCa, 694 without PCa) underwent ≥10 core biopsies. Serum concentrations of tPSA, fPSA (both calibrated against a WHO reference material), and p2PSA were measured on Access2 or DxI800 analyzers (Beckman Coulter).
Results: The percentage ratio of p2PSA to fPSA (%p2PSA) and Phi were significantly higher in all PCa subcohorts (positive initial or repeat biopsy result or negative digital rectal examination) (P < 0.0001) compared with patients without PCa. Phi had the largest area under the ROC curve (AUC) (AUC = 0.74) and provided significantly better clinical performance for predicting PCa compared with %p2PSA (AUC = 0.72, P = 0.018), p2PSA (AUC = 0.63, P < 0.0001), %fPSA (AUC = 0.61) or tPSA (AUC = 0.56). Significantly higher median values of Phi were observed for patients with a Gleason score ≥7 (Phi = 60) compared with a Gleason score <7 phi="" p="" the="" proportion="" of="" aggressive="" pca="" gleason="" score="" 7="" increased="" with=""
Conclusions:="" results="" this="" multicenter="" study="" show="" that="" compared="" tpsa="" or="" fpsa="" demonstrated="" superior="" clinical="" performance="" in="" detecting="" at="" 1="" 6-8="" 0="" g="" l="" i="" e="" approximately="" 2-10="" traditional="" calibration="" and="" is="" better="" able="" to="" detect="">
Written by:
Stephan C, Vincendeau S, Houlgatte A, Cammann H, Jung K, Semjonow A Are you the author?
Department of Urology, Charité-Universitätsmedizin Berlin, Berlin, Germany
Reference: Clin Chem. 2013 Jan;59(1):306-14
doi: 10.1373/clinchem.2012.195784
PubMed Abstract
PMID: 23213080
