Biological markers in breast carcinoma: III. Clinical correlations with carcinoembryonic antigen

Plasma CEA levels were evaluated by radioimmunoassay in patients with breast carcinoma in relation to clinical‐pathologic staging, clinical tumor burden, prognosis and organ sites of involvement. Elevated levels were observed in 83/117 (70.9%) patients with metastatic disease, 2/14 preoperative patients and in 3/39 one‐six month postoperative patients. Preoperative levels were elevated in two patients; the levels fell to normal after operation. Changes of elevated CEA levels followed the clinical response to therapy in 22/22 metastatic disease patient‐trials. The levels decreased with a response in 15 trials and rose with progressive disease or relapse in seven trials. The incidence of CEA elevations and quantitative CEA levels both rose with increasing clinical tumor burden from the postoperative state through the preoperative state to two or more organ sites of metastatic involvement. No relationship was demonstrable among limited samples between preoperative or postoperative CEA levels and prognosis; however, in metastatic disease, pretherapy CEA levels >5 ng/ml were associated with low response rates and early therapeutic failure to chemotherapy. The highest frequency of elevated CEA levels was observed in patients with osseous involvement (79%) and the lowest frequency with skin (52%) and breast (50%) metastases. Liver and osseous disease were also associated with higher mean CEA levels than were other sites of metastatic involvement. CEA levels appear to be elevated in the majority of patients with metastatic disease and be of prognostic importance in metastatic disease. The level in patients with metastatic disease appears to reflect the therapy‐associated tumor burden of the host, especially in patients with elevated levels.