Simple method for comparing reliability of two serum tumour markers in breast carcinoma.

Abstract

To compare the two breast tumour markers, CA15-3 and mucinous-like carcinoma associated antigen (MCA), using Receiver Operating Characteristic (ROC) curve analysis. One hundred and ninety six patients "presenting" with breast carcinoma had serum CA15-3 and MCA concentrations measured. Using these markers as indicators of stage IV disease at the recommended laboratory level, true positive rates (TPR) and false positive rates (FPR) were obtained as follows: CA15-3 TPR = 75%, FPR = 7.4%, MCA TPR = 80%, FPR = 59.1%. By increasing the CA15-3 cutoff level to 45 U/ml, a TPR and FPR of 75% and 0.6%, respectively were obtained. By increasing the MCA cutoff level to 23 U/ml, a TPR and FPR of 65% and 2.3%, respectively, were obtained. Using ROC curve analysis shows that CA15-3 is a superior indicator of metastatic breast disease than MCA at recommended laboratory levels, and by altering the cutoff points, the specificity and sensitivity for both these markers can be improved.