Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 ?g/L: Are they useful tools for early detection and screening of prostate cancer?

Abstract

Molecular forms of prostate-specific antigen (PSA) improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) in men with total PSA concentrations between 4 and 10 g/l. To evaluate the diagnostic utility of free PSA (fPSA) and complexed PSA forms for identification of men with PCa in the low PSA range of <4 g/l, total PSA (tPSA), ␣ 1 -antichymotrypsin complexed PSA (PSA-ACT) and fPSA (Roche Elecsys [ES] system) as well as tPSA and complexed PSA (cPSA) (Bayer Immuno 1 system) were measured in archival serum samples from 31 untreated patients with PCa, 66 patients with BPH, and 90 men without prostatic disease. The median ratios of fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were significantly different between patients with BPH and PCa (27.2 vs. 19.4%, 64 vs. 88%, 77.2 vs. 88.2%, p < 0.05). No associations between PSA forms and tumor stage and grade were found. Analysis of the receiver operating characteristic curves showed that these ratios could discriminate better between BPH and PCa patients than determination of the analytes tPSA, fPSA, cPSA and PSA-ACT alone. The use of one of the ratios would have eliminated roughly half of the unnecessary biopsies in this study. The ratios should be considered as potential tools to increase the selectivity of PCa detection at low PSA concentration. The ratios fPSA/tPSA and cPSA/tPSA can be determined using commercially available assays so that one of these ratios could be preferred instead of PSA-ACT determination. The ratios could be useful in assessing the risk of PCa in the individual and therefore in deciding on prostate biopsy for final diagnosis.

The ratio of prostate‐specific antigen (PSA) to prostate volume (PSA density) as a parameter to improve the detection of prostate carcinoma in PSA values in the range of < 4 ng/mL

“…Some studies demonstrated an advantage for %fPSA, 25,46 -48 and some did not demonstrate a better performance by %fPSA compared with tPSA. 49 -52 Retrospective data obtained by Jung et al 48 revealed an advantage for %fPSA compared with tPSA. In a larger group of men (n ϭ 219 patients) with tPSA in the 2-4 ng/mL range, there was no difference between tPSA and %fPSA (AUC, 0.62 vs. 0.64).…”

PSA y hK2 en el diagnóstico de cáncer de próstata

“…Para sensibilidades del 90% y 95% con el PSA complejo obtienen especificidades de 25,6% y 20,1% respectivamente, mientras que con el PSA total serían de 11,1% y 9,8%. Sin embargo, Lein et al 58 y Jung et al 59 no encuentran ventajas del PSA complejo con respecto al PSA total, aunque las poblaciones estudiadas y los ensayos para medir el PSA total fueron distintos. Lein et al 58 sí que describen estas ventajas cuando analizan el cociente PSA complejo/PSA total.…”

Prostate-specific antigen, its molecular forms, and other kallikrein markers for detection of prostate cancer

“…41 Studies on the use of the PSA complexes (PSA-ACT and cPSA) for low PSA values less than 4 ng/mL are rare, but these results indicate a possible use and warrant further prospective evaluations. 42,43 …”