The relationship between circulating carcinoembryonic antigen (CEA) levels and parameters of primary tumor and metastases in breast cancer patients.

AIM The Carcinoembryonic antigen (CEA) is used as a tumor marker for breast cancer (BC). In order to better define clinical usefulness of CEA in breast cancer patients (BCP) we determined its baseline pre-treatment levels and correlated them with main parameters of primary tumor and metastases. PATIENTS AND METHODS The main experimental group consisted of 47 female patients with histologically confirmed diagnosis of BC. The obtained results have been compared with those of two control groups: clinically healthy women, and patients with other types and locations of cancer. In both cancer groups the parameters of primary tumor (size, grade) and metastases (time interval to metastases, location, size) have been determined. Circulating levels of CEA were measured by the means of immunoradiometric assay. Results were processed by means of t-test, two way analysis of variance in F-test, and logistic general linear model with calculations of Pearson's correlation coefficient. RESULTS Baseline levels of CEA in BCP were significantly higher than in healthy women (p < 0.0001), and in patients with other types and locations of cancer (p < 0.007). There also was significant difference (p < 0.001) between serum CEA in other cancer patients and healthy women. Baseline CEA levels were in significant positive correlation with the size of primary tumor both in all BCP (p < 0.03) and in hyperCEA BCP (p < 0.002), while in other cancer patients such a correlation did not exist. There was no correlation between CEA and degree of differentiation of primary tumor either in BCP or in other cancer patients. The average circulating levels of CEA in metastatic BCP were significantly higher (p < 0.03) in comparison to non-metastatic patients, while in other cancer patients such a difference did not show up. There was significant correlation (p < 0.0001) between circulating CEA and the size of metastases in all BCP and in subgroup of hyperCEA BCP, while in other cancer patients it was not a case. There was no correlation between serum CEA and other two metastatic parameters either in BCP or in other cancer patients. CONCLUSIONS CEA does not have high tumor specificity for BC since its baseline levels may be elevated in other types of cancer. Circulating levels of CEA in BCP are directly dependable on the size of both primary and metastatic tumor. CEA is a tumor antigen of less differentiated cancer cells. Circulating CEA is a good prognostic marker for patients with metastatic BC.