RATIO OF FREE-PSA TOTAL-PSA - AN INDICATO R FOR DIFFERENTIATION BETWEEN PATIENTS WITH PROSTATE-CANCER AND BENIGN PROSTATIC HYPERPLASIA/

A survey on literature data concerning free prostate specific antigen and the corresponding cut-offs for f-PSA/t-PSA differentiating patient s suffering from prostate carcinoma and benign prostatic hyperplasia i s given. The essential importance of the diagnostic criterion for esta blishing the cut-off value is demonstrated. On the basis of own data, the application of the parameter f-PSA/t-PSA is recommended as additio nal criterion. F-PSA and t-PSA were determined in serum samples of 149 patients (45 with prostate cancer, 50 with benign prostate hyperplasi a, 54 healthy controls) using the IMMULITE test. According to the IMMU LITE test results, median values for t-PSA (f-PSA) were 1.59 (0.29) mu g/l in healthy men, 7.90 (0.80) mu g/l in patients with PCa and 4.30 (0.81) mu g/l in patients with benign prostatic hyperplasia. The perce ntage of f-PSA (f-PSA/t-PSA) was significantly lower in patients with PCa (median value: 9.5% in the IMMULITE test) compared to patients wit h BPH (21.2%) and healthy controls (23.7%). The receiver-operation-cha racteristics analyzis (ROC) shows, compared to t-PSA alone, obtaining the percentage of f-PSA significantly improves the ability to differen tiate between PCa and BPH as well as healthy controls. For reasons of diagnostic efficiency, a cut-off for the percentage of f-PSA (f-PSA%) of 15% is suggested for the IMMULITE test.