It is well established that the presence of axillary nodal metastases is the most important prognostic factor in primary operable breast cancer. However, it has also been shown that 15-30% of patients without lymph node metastases as assessed by light microscopy have recurrence within 10 years. In this study, our aim was first to investigate the diagnostic value of immunohistochemical staining in detecting micrometastases and secondly to correlate their presence with prognosis (recurrence and survival).

We retrospectively analyzed 492 axillary nodes from 49 consecutive node-negative invasive breast cancers treated at Kyung-Hee University Hospital from 1991 to 1995 with average follow-up of 60.2 (21-100) months. An additional section of original paraffin blocks was cut and stained by immunohistochemical technique using monoclonal antibodies (AE 1/3 and No.7) to cytokeratin.

Micrometastases with individual cell and cell clusters were readily detected by this technique in 27% of the cases. There were no predictors of micrometastases among the clinicopathological data of patients. The presence of micrometastases was not associated with disease-free and overall survival but 10coMregional recurrence rate.

A combination of immunohistochemistry and serial sectioning of axillary lymph node would help evaluate the significance of occult axillary metastases. Patients with node-negative disease may relapse after many years and prolonged follow-up is required to establish the role of micrometastases. Such an approach, together with a search for bone marrow micrometastases and epidemiologic, cilinical, pathologic and/or biochemical prognostic factors, may serve to identify high risk patients in the presumed node-negative group. It would provide a rational basis for the selective use of adjuvant therapy.