The role of CA 15-3 and MCA monoclonal antibody assays in the detection of primary and recurrent breast cancer.

CA 15-3 and MCA assays were tested in 103 operable patients (preoperative determination) and 100 patients with advanced breast cancer. Normal CA 15-3 and MCA values were determined in a series of 68 healthy women. The negative/positive cut-off was set at 28.8 U/ml and 15.5 U/ml respectively for CA 15-3 and MCA (mean value + 2SD). Results were analyzed in the two groups and with respect to T and N pathological categories in the preoperative series. In pT1 (59 pts), pT2 (30 pts), pT3 + pT4 (14 pts), pNO (58 pts), pN1 (45 pts) and overall preoperative series CA 15-3 and MCA sensitivities were respectively 25%, 40%, 57%, 22%, 42%, 30% and 27%, 30%, 35%, 21%, 33%, 26%. In the patients affected by widespread disease, sensitivity was 92% and 80% for CA 15-3 and MCA. Results were significantly different among normal, preoperative and advanced patients (P less than 0.05). Our results suggest that CA 15-3 and MCA levels are correlated with the tumor mass. Nevertheless, the low sensitivity in pT1 and pNO cases indicates that these two assays have no role in the diagnosis of early breast cancer. In the advanced patients, too, the results can be questioned: in the present study, in fact, recurrent cases were characterized by gross disease with multiple site involvement and cannot be considered as an example of early diagnosis of breast cancer recurrence.