Biochemical Markers and Skeletal Metabolism in Carcinoma of the Prostate: Use of Decision Matrix Theory and ROC Analysis

The discriminative ability of several skeletal and tumour markers was assessed in 102 patients with prostatic disease. These comprised serum acid and alkaline phosphatase, serum albumin and osteocalcin, urinary excretion of calcium, hydroxyproline and 6-oxo prostaglandin F1 alpha. None of the tests was of value in distinguishing patients with benign prostatic disease from those with tumour not involving the skeleton. Values of serum osteocalcin, urinary excretion of calcium and urinary 6-oxo prostaglandin F1 alpha failed to discriminate significantly between patients with or without metastases. The remaining four markers were compared by decision matrix analysis and receiver operating characteristic (ROC) curves. Serum alkaline phosphatase provided the most sensitive marker of skeletal metastases (80.5%), followed by serum acid phosphatase (80%), hydroxyproline (68%) and albumin (30%). ROC analysis suggested that alkaline phosphatase conformed most closely to the "ideal marker" with highest specificity and sensitivity.