Optimizing tumor markers in breast cancer: monitoring, prognosis, and therapy control.

The clinical validity of tumor markers in breast cancer is reevaluated. Though ideal tumor markers are presently not available for breast cancer patients, optimizing markers can be achieved, applying markers in special situations and in selected fields of oncology. Tumor markers like carcinoembryonic antigen (CEA) and tissue polypeptide antigen are only of limited value in the primary diagnosis of breast cancer due to their low sensitivity and their poor specificity. Single postsurgical CEA values in selected groups of mammary carcinomas, however, can be used to predict patients with high risk of recurrence and they imply considerable prognostic information. Serial CEA determination in the follow-up of patients with operated breast cancer are highly sensitive in early detection of recurrences and are also useful in controlling therapy in individual cases. The biological basis of tumor marker measurements reflecting tumor growth is pointed out and newly developed methodologies for the potential establishment of more specific tumor markers for serodiagnosis and for immunolocalization of tumors are discussed.