Metastatic workup of patients with prostate cancer employing skeletal alkaline phosphatase

Purpose: To compare the efficacy of two tests, prostate-specific antigen (PSA) and skeletal alkaline phosphatase (SAP) as staging markers to discriminate patients with cancer of the prostate (CaP) with bony metastases (MI) from those without bony metastases (Mo). Material and Methods: Forty-seven untreated patients with Mo (n=26) and MI (n=21) CaP were entered in this study. Serum concentrations for SAP and PSA were determined using two immunoassays. Results: None of the Mo patients but 65% of the MI patients exhibited a SAP value above the reference range (< 19 ng/ml). A corresponding cutt-offpoint of 100 ng/ml for PSA showed that 27% of Mo patients and only 65% of the M1 patients exhibited a value > 100 ng/ml. This resulted in a sensitivity and specificity of 65% and 100% for SAP and 65% and 73% for PSA. Conclusion: Our findings suggest that SAP could become a useful marker in the evaluation of patients with newly diagnosed CaP as it seems to provide additional information concerning the skeletal status of these patients.