On reference values for tumor markers in prostatic carcinoma.

Serum contents of prostatic acid phosphatase, neopterin, osteocalcin, tissue polypeptide antigen and CA-50 were measured before onset of treatment in 83 patients suffering from prostatic carcinoma. In an attempt to identify patients with poor prognosis the data were related to patient survival after 2 years. It was found that the standard cut off values, obtained from the upper limits of normal, healthy subjects, were sensitive but had low specificity. A better relation to prognosis was usually found at a higher discrimination limit. The degree of elevation appears more important than the elevation of the markers as such in indicating a poor prognosis. By systematic adjustment of the discrimination levels, higher specificity can be obtained with little loss of sensitivity.