Follow-up of metastatic breast cancer patients with a mucin-like carcinoma-associated antigen: comparison to CA 15.3 and carcinoembryonic antigen.

During a follow-up program, breast cancer patients were monitored with serum analyses of mucin-like carcinoma-associated antigen (MCA), CA 15.3 and carcinoembryonic antigen (CEA). Minimum as well as maximum marker values of the individual patterns were selected for further evaluation. Marker levels of risk patients differed significantly from those of patients with metastases. In several risk patients, elevated marker levels (especially of MCA) preceded clinical diagnosis of metastases for several months. In cases with already diagnosed metastases, sensitivity of MCA was comparable to CA 15.3 or CEA. The type of metastases determined marker sensitivity, concentration and the difference between maximum and minimum values.