Diagnostic efficiency of biological markers in blood serum on prostate cancer: a comparison of four different markers and 12 different methods.

Serum-acid phosphatase as measured by nine different methods, serum prostate-specific antigen, cancer antigen CA-50, and creatine kinase BB isoenzyme have been evaluated and compared with respect to efficiency in differentiating between prostate cancer and benign hyperplasia. The patient material consisted of 92 prostate cancer patients (59 untreated, and 33 previously treated), 106 patients with benign hyperplasia and 66 patients with non-prostatic urological diseases. The cancer group was classified according to the TNM-system, and also graded according to histopathological findings. The following main conclusions were drawn. Acid phosphatase activity, when measured with continuous monitoring procedure (substrate: alpha-naphthyl phosphate), showed on the average slightly, but statistically not significant higher diagnostic efficiency than when measured with conventional two-point discontinuous monitoring method (substrate: p-nitrophenyl phosphate). There was no or only marginal differences in diagnostic efficiency between activity measurements of the total acid phosphatase and the tartrate-labile fraction, and also between activity measurements and immunological measurements (PAP-RIA and PAP-IEA). Prostate-specific antigen was found to have statistically significant higher diagnostic efficiency than acid phosphatase, the former being positive in 17 of 25 patients with prostate cancer without distant metastases, and in six of 11 patients classified as T0-2 M0. Cancer antigen CA-50 and creatine kinase BB isoenzyme appeared to be of little diagnostic value. From a cost-effective point of view, total or tartrate-labile prostatic acid phosphatase activity, as measured by continuous monitoring technique with alpha-naphthyl phosphate as substrate, is suggested suitable as a first-choice parameter both for diagnostic and monitoring purposes with respect to prostate disease. Prostate-specific antigen may give additional information, and should be considered analysed on special request.