Diagnostic significance of the tumour markers CEA, CA 15-3 and CA 125 in malignant effusions in breast cancer.

Concentrations of the tumour-associated antigens CEA, CA 15-3 and CA 125 were determined in serous effusions (EF) from patients (pts) with breast cancer. As controls, serous effusions from patients with benign and other malignant diseases were used. The EF levels were also compared with those of serum. CA 15-3 was elevated (greater than 35 U/ml) in 65.7% of breast cancer EF, in 39.3% of EF in various other malignant diseases and in 0% of benign EF. CEA was elevated (greater than 9 ng/ml) in 37.5% of breast cancer EF, in 17.9% of EF of various other malignant diseases and in 27% of benign EF. CA 125 was elevated (greater than 35 U/ml) in 93.8% of breast cancer EF, in 78.6% of EF of various other malignant diseases and in 58.8% of benign EF. There was a statistically significant correlation between EF and serum values for the markers studied. Sensitivity and specificity for CA 15-3 were 65.7% and 76.6%, for CEA 37.5% and 77.7% and for CA 125 93.8% and 28.7%, respectively. CA 15-3 is a marker with definite diagnostic accuracy compared to CEA and CA 125 in breast cancer EF. CA 125 appears to derive from proliferating mesothelia rather than cancer cells alone and occurs in a broad spectrum of malignant as well as benign EF. The above markers should not be used alone for diagnosis of breast cancer in patients with serous effusions.