Intraoperative imprint cytologic assessment of the sentinel node for early breast cancer.

An increasing number of patients are undergoing sentinel node biopsy alone for axillary staging of early breast cancer. A reliable method for evaluating the status of the sentinel node intraoperatively would allow patients with sentinel node metastases to undergo immediate rather than delayed axillary clearance. Sentinel nodes in 53 consecutive patients were examined by intraoperative imprint cytology. When compared with subsequent analysis by hematoxylin-eosin staining and immunohistochemistry, the accuracy of imprint cytology for the detecting nodal metastases was 81.1%; the false negative rate was 47.0%, and there were no false positives. Results were made available to the operating surgeon within a mean time of 25 minutes. All but one of the false negatives involved micrometastatic deposits of less than 0.1 mm. Intraoperative imprint cytologic examination of the sentinel node is a useful technique that can be performed efficiently and without loss of nodal tissue for subsequent analysis. With the use of this technique, more than 50% of lymph node-positive patients would potentially be spared a second operation.