Use of Tumor Markers for Patient Monitoring in Breast Cancer
Monitoring of patients with breast cancer under therapy is based on the results of our previous studies on the surveillance of approximately 1000 patients in clinical routine since 1979. As we have shown before, tissue polypeptide antigen (TPA) and carcinoembryonic antigen (CEA) are highly potential markers in the follow-up of various malignancies. In breast cancer, statistical analysis demonstrated that both markers, each separately, had more discriminatory power than 18 other common laboratory parameters taken together. In combination, TPA and CEA were able to discriminate at 95% probability between patients with progressive disease and those without evidence of disease. On this basis, the two markers can well serve as an aid in diagnosing early recurrence and in monitoring therapy. In the follow-up of breast cancer cases undergoing cytotoxic chemotherapy and/or hormone therapy, we have found that the concordance with the clinical status amounted to 91% in TPA, 77% in CEA, and 71% in TPA + CEA. The lower concordance of CEA in comparison with TPA is due to differences in cellular development and secretion of the markers into the peripheral blood stream. Our findings are in general agreement with those of other clinicians. The importance of marker analysis is accentuated by the fact that in 11% of patients, a recurrence was indicated by TPA or CEA marker analysis only, whereas the usual diagnostic means including clinical findings failed.