Longitudinal follow-up of breast cancer patients with the tumor markers CA 549 and CA 15.3

In order to verify the efficiency of the tumor markers CA 15.3 and CA 549 in the follow-up of breast cancer patients, it was necessary first to check the cutoff levels of each tumor marker in women with an increased age-related risk, but with no evidence of disease. From 132 serum samples in this age group, we confirmed the CA 549 cutoff level of 12.1 U/ml. However, the cutoff of CA 15.3 was 34 U/ml, which is higher than previously reported in the literature. Fifty-two breast cancer patients with or without metastases at the time of entry into the study were followed for 2 to 3 years with both tumor markers. The sensitivity, specificity and the test efficiency for the presence of metastases were analyzed with each tumor marker. Taking into account the different cutoff levels, we concluded that both tumor markers can be used independently to follow the clinical situation of patients. In several cases an increase in both tumor markers was observed before a clinical diagnosis of metastases could be made. Combination of these two tumor markers gave no more significant information about the patient's clinical situation than each tumor marker alone.