ABSTRACT
An immunoradiometric assay [IRMA] has been used to determine circulating levels of the breast-associated antigen, CA 15.3. Eighty patients with breast cancer who had undergone mastectomy have been studied. Using the classification of TNM clinical stage of breast cancer, they were divided into two groups; the group who had local rearrence and-or metastasis [30 patients] and those who were clinically and radiologically disease-free [50 patients]. Their sera levels for the antigen were correlated with normal female individuals [30 subjects]. The sensitivity rate in recurrent or metastatic group was 73.3% and the spedficity for differentiation between this group and disease free was 90%. Among those with recurrent or metastatic breast cancer the CA 15.3 is highest in patients with local recurrence [sensitivity 87.5%]. High sensitivity rate were also found in patients with liver metastasis [80%], bone metastasis [71.4%], and pulmonary metastasis [62.5%]. It is suggested that CA 15.3 measurements for breast cancer patients maybe very valuable for early detection of metastasis or for monitoring the clinical course of the disease