These investigators assessed the operating characteristics of Beckman Coulter phi in the 2-4 and 4-10ng/mL PSA ranges. The Receiver Operating Characteristics (ROC) curve of phi was evaluated and compared to those of %free PSA and total PSA. Two hundred thirty four men with PSA 2-4ng/mL and 658 men with PSA 4-10ng/mL were enrolled at 7 sites. Participants were ≥50 years, had a non-suspicious DRE, a biopsy- confirmed diagnosis. The PSA, free PSA, and [-2]proPSA concentrations were all determined using the Beckman Coulter Access 2 Immunoassay Analyzer. The Beckman Coulter phi was calculated as ([-2]proPSA/free PSA)x(PSA)).
They found the AUC for phi comparable in both PSA ranges; AUC= 0.708 for the PSA 4-10ng/mL range, and AUC= 0.701 for the PSA 2-4ng/mL range. The combined AUC for the 2-10 PSA range was AUC = 0.703. The AUC for phi was significantly better in the established PSA range of 4-10ng/mL with the AUC for PSA=0.516 (<0.001), and %free PSA=0.648 (0.009). He concluded that that phi has improved clinical specificity compared to PSA and %free PSA and may be useful for aiding biopsy decisions and patient management.
Presented by William J. Catalona, et al. at the American Urological Association (AUA) Annual Meeting - May 14 - 19, 2011 - Walter E. Washington Convention Center, Washington, DC USA
Reported for UroToday by Christopher P. Evans, MD, FACS, Professor and Chairman, Department of Urology, University of California, Davis, School of Medicine.
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