Diagnostic significance of [-2]pro-PSA and prostate dimension-adjusted PSA-related indices in men with total PSA in the 2.0-10.0 ng/mL range.

PURPOSE

One of the most important issues to address when developing an optimal screening system for prostate cancer is investigating appropriate biopsy indications following serum prostate-specific antigen (PSA) measurements in order to maintain high sensitivity and avoid unnecessary biopsy.

METHODS

Between April 2004 and December 2007, 239 consecutive men with total PSA levels of 2.0-10.0 ng/mL underwent measurements of PSA, free PSA, and [-2]pro-PSA. We assessed the significance of laboratory-based PSA-related indices including free PSA/total PSA (%f-PSA), p2PSA/free PSA (%p2PSA), p2PSA/%f-PSA, Prostate Health Index (phi, an index combining PSA, free PSA, and p2PSA), total prostate volume (TPV)-adjusted PSA-related indices, including PSA density, %p2PSA density, p2PSA/%f-PSA density, and phi density, and transition zone (TZ) prostate volume-adjusted PSA-related indices such as PSA TZ density (PSATZD), %p2PSA TZD, p2PSA/%fPSA TZD, and phi TZD.

RESULTS

The positive biopsy rate was 22.2%. When sensitivity was fixed at 95 %, unnecessary biopsies could be avoided in 28% of men when phi was used as a biopsy indication. In cases where total and transition zone prostate volumes were available, the use of %p2PSA density, phi density, p2PSA/%f-PSA TZD, and phi TZD resulted in the avoidance of 48, 47, 54, and 54 % of unnecessary biopsies, respectively, while maintaining a high sensitivity of 90%.

CONCLUSIONS

At 90 and 95 % sensitivity, laboratory-based indices containing p2PSA, particularly phi, showed significantly greater specificity for prostate cancer as compared with %f-PSA. The diagnostic accuracy of prostate volume-adjusted p2PSA-related indices could be excellent, particularly the transition zone volume-adjusted indices at fixed sensitivities of 95 and 90%.