Additional use of [−2] precursor prostate-specific antigen and “benign” PSA at diagnosis in screen-detected prostate cancer

Abstract

Objectives To evaluate the adjuvant clinical use of [−2] precursor prostate-specific antigen ([−2]pPSA), which is associated with prostate cancer (PCa), and “benign” PSA, related to benign prostatic hyperplasia, in selecting a treatment strategy in patients with screen-detected PCa. Methods Research-use immunoassays (Beckman Coulter) were used to measure [−2]pPSA, sum [−7, −5, −4, and −2]pPSA, and benign PSA from the frozen serum of participants from the screen arm of the European Randomized Study of Screening for Prostate Cancer, section Rotterdam, diagnosed with PCa with a serum PSA level lower than 15 ng/mL. We compared men with relatively benign PCa (Epstein’s criteria; group 1) and men with arbitrarily defined aggressive PCa characteristics (Gleason score greater than 4 + 4 and more than four cores with PCa invasion or pT3C disease; group 2). Results The data of 61 patients were evaluated. The median age in both groups was 68 years. Total PSA performed best in a univariate analysis, although in the multivariate analysis, the combination of pPSA and percent free PSA could correctly predict 95.5% of group 1 and 82.4% of group 2. The pPSA and percent free PSA forms remained statistically significant in the multivariate analysis of a subgroup of 30 participants normalized for PSA level and prostate volume; combined they correctly identified 89.5% and 54.5% of patients identified as having relatively favorable and aggressive PCa characteristics, respectively. Conclusions Adjuvant clinical use of pPSA over traditional parameters in selecting treatment strategies for men with PCa cannot yet be definitely determined. However, the promising results in a subgroup analysis warrant further investigation.