Detection of breast cancer micrometastases in peripheral blood using immunomagnetic separation and immunocytochemistry.

Abstract

Although there have been many reports on the immunocytochemical detection of bone marrow micrometastases in breast cancer patients, peripheral blood micrometastases (PBM) have rarely been studied by immunocytochemistry (ICC). PBM in operable and metastatic breast cancer patients were studied using immunomagnetic separation of tumor cells followed by immunocytochemistry (IMS-ICC). PBM were not detected in any peripheral blood samples from 21 healthy women, six patients with benign disease, or in a 21 patients with primary operable breast cancer, of which there were 7 stage I (n=7), 9 stage II, 2 stage III, and 3 inflammatory tumors. On the other hand, PBM were detected in 8 of 29 patients with metastatic breast cancers (27.6%). The number of tumor cells per patient varied from 2 to 90 cancer cells (median: 8 cells). Positivity of PBM was not significantly associated with the first site of recurrence, number of involved organs, tumor marker status, performance status, or disease-free interval, but it was significantly (p<0.01) associated with progesterone receptor negativity. PBM are very rare in primary operable breast cancer patients but can be observed in a considerable number of metastatic breast cancer patients. The clinical significance of PBM still remains to be established.