Efficacy of skeletal alkaline phosphatase and prostate-specific antigen in the diagnosis of bone metastasis in cancer of the prostate.

Purpose: To study the efficacy of prostate-specific antigen (PSA) and skeletal alkaline phosphatase (SAP) as staging markers in discriminating patients with cancer of the prostate (CaP) with (M+) and without bone metastases (M0).

Material And Methods: 73 patients with untreated CaP entered the study. After staging the patients were divided into 3 groups: group I, patients with CaP and bone metastases (n = 21); group II, patients with locally advanced CaP without bone metastases (n = 26), and group III, patients with clinically localized CaP without bone metastases (n = 26).

Results: None of the M0 patients but 71% of the M+ patients exhibited an increased SAP. A corresponding cutoff point of 100 ng/ml for PSA showed that 19% of M0 patients and 71% of the M+ patients exhibited a value of >100 ng/ml. This resulted in a sensitivity and specificity of 71 and 100% of SAP and 71 and 81% for PSA, respectively.

Conclusion: SAP could become a useful marker in the evaluation of patients with newly diagnosed CaP as it provides additional information concerning the skeletal status of these patients.