Determination of serum tumor markers TPS and CA 15-3 during monitoring of treatment in metastatic breast cancer patients.

Serum levels of tissue polypeptide specific antigen (TPS), a cytokeratin 18 marker, and CA 15-3 were determined in 42 patients with metastatic breast cancer during routine treatment follow-up. At the time of proved metastatic disease, 86% of the values for TPS were above the upper reference value as compared to 93% for CA 15-3. The combined use of TPS and CA 15-3 increased the overall sensitivity. The levels of the tumor markers followed the course of disease during a follow-up period of 6-10 months, even though the dynamics of the changes of tumor markers levels differed in some patients. An increase in the tumor marker level of 25% or more was seen in 60% (TPS) and 52% (CA 15-3), respectively of the studied patients. TPS appeared to indicate changes faster than CA 15-3. The overall results of this study suggest the combined use of TPS and CA 15-3 in the monitoring of breast cancer patients is preferable.