A Multicenter Clinical Trial on the use of alpha(1)-antichymotrypsin-prostate-specific antigen in prostate cancer diagnosis

BACKGROUND. The aim was to evaluate the clinical performance of alpha(1)-an tichymotrypsin prostate-specific antigen (PSA-ACT) for early diagnosis of p rostate cancer (PCa) in a multicenter trial. METHODS. Three hundred sixty-seven white men with PCa and 290 with benign p rostatic hyperplasia (BPH) with tPSA concentrations between 2 and 20 mug/L were analyzed. The Elecsys system 2010 (Roche Diagnostics, Germany) was use d for determination of total PSA (tPSA) and free PSA (fPSA). The PSA-ACT te st was a prototype assay used on the ES system (Roche Diagnostics). RESULTS. The median concentrations of tPSA (PCa: 8.43 mug/L vs. BPH: 6.60 m ug/L) and PSA-ACT (8.30 mug/L vs. 6.46 mug/L) were significantly different, respectively. The median ratios of fPSA/tPSA (PCa: 12% vs. BPH: 16%) and P SA-ACT/tPSA (98% vs. 95%) were significantly different. Receiver operating characteristics (ROC) analysis for discrimination between PC and BPH (tPSA between 2 and 20 mug/L) was performed with 252 matched pairs and showed tha t the area under the curve (AUC) of the ratio fPSA/tPSA (0.66) was signific antly different from tPSA (0.50) and PSA-ACT (0.52). PSA-ACT alone or the r atio PSA-ACT/tPSA (0.56) were not significantly different from tPSA. For tP SA between 4 and 10 mug/L (n = 145 pairs), the AUC of the ratio fPSA/tPSA ( 0.65) was significantly higher than tPSA (0.50) and PSA-ACT (0.54). Signifi cant differences between tPSA and PSA-ACT or PSA-ACT/tPSA (0.56) were not f ound. CONCLUSIONS. The determination of PSA-ACT as well as the PSA-ACT/tPSA ratio did not improve the diagnostic impact in patients undergoing evaluation fo r PCa compared to fPSA/tPSA ratio. Prostate 47:77-84, 2001. (C) 2001 Wiley- Liss, Inc.