[Considerations in rational use of tumor markers in breast carcinoma]

The objective of this review is to determine clinical practical guidelines for the use of serum tumor markers in the care of breast cancer patients outside of clinical trials. Mucin antigens (CA 15-3, MCA, CA 549) and CEA are established markers in breast cancer. Owing to their low sensitivity, none of these markers can be recommended for screening, diagnosis or staging. During follow-up, increasing marker levels may indicate recurrence 3-6 months earlier than clinical and radiological examinations in about 40-50% of patients. However, the clinical benefit of this lead-time is not established. Tumor markers are able to monitor response to treatment in 70-80% of patients with metastatic breast cancer. However, paradoxical changes of the markers especially in the beginning of treatment, the insufficient concordance with tumor activity in 20-30% of the women, and the lack of curative therapy regimens limit the prospective clinical use of the markers in the individual patient. Therefore, marker changes require confirmation by radiological methods in most cases. The present data are insufficient to recommend routine use of tumor markers alone for monitoring breast cancer patients after primary treatment or during palliative therapy. However, in the absence of readily measurable disease (e. g. bone metastases) continuously increasing marker levels may be used to indicate treatment failure. If high-dose chemotherapy in metastatic breast cancer renders to be effective, the clinical impact of tumor markers will increase considerably. Until that time, the analytical performance and the sensitivity of the established marker assays should be improved, and the clinical role of newer marker tests (TPS, CA 27.29) should be evaluated.