Background: The description of the different forms of circulating PSA has opened a new strategy in the diagnosis of prostate cancer. The aim of our study was to assess the diagnostic potential of PSA and the PSA fractions in the diagnosis of benign prostate hyperplasia (BPH) and prostate cancer.
Patients and methods: We measured the serum levels of PSA (Elecsys 2010, Roche Diagnostics, Mannheim, Germany), complexed PSA (Immuno 1 system, Bayer, Tarrytown, NY USA) and free PSA (Elecsys 2010, Roche Diagnostics, Mannheim, Germany) in 178 patients with BPH and 44 patients with prostate cancer.
Results: ROC curves were used for comparison of the diagnostic utility of the tests assessed. The biggest areas under the curve were obtained for the ratios between free/complexed PSA and free/total PSA (0.887 and 0.872, respectively). When choosing the cut-off values to obtain a 90% sensibility, we found that the specificity for the free/total PSA ratio was 59% and for the free/complexed PSA ratio 72%.
Conclusion: Our results suggest that replacement of the measurement of total PSA by complexed PSA in prostate cancer diagnosis may be interesting. Nevertheless, as this is a retrospective study limited to a small number of patients, it is obvious that we need more data to make a final decision with regard to this subject.