[Initial experiences with CA-15-3 determination in the serum of patients with breast cancer].

CA 15-3 levels were determined immunoradiometrically in sera of 63 women with breast cancer (44 with stage I to III cancer, pre-operatively, 5 with local recurrence or lymphnode metastases and 14 patients with distant metastases) and 30 women with benign breast tumours or fibrocystic disease. 32% elevated levels (greater than 25 U/ml) have been found in all carcinomas compared with 7% in 44 patients without any evidence of disease (NED) and 0% in the benign lesions. In locally limited breast carcinomas, the very low pre-operative sensitivity of 16% prevents early tumour detection, whereas in patients with distant metastases a sensitivity of 86% (12 out of 14) has been found. In follow-up, continuous rising of CA 15-3 levels reveals metastatic or progressive disease with a great accuracy, decreasing serum values were only found in cases of remission. A positive correlation between the actual clinical situation in follow-up and the changes in these tumour marker levels has been observed in 87%. The CA 15-3 test system seems to be useful assay for patients with breast cancer with respect to earlier detection of distant metastases, especially of osseous type. This tumour marker is not suitable for screening or early diagnosis of small tumour recurrence in the follow-up of breast cancer patients.