Intraoperative evaluation of axillary sentinel lymph nodes using touch imprint cytology and immunohistochemistry. Part II. Results.

AIM: In order to operate selectively on positive axillae during the initial operative session for early breast cancer, an accurate and rapid intraoperative method to examine an axillary node sample (ANS) or a sentinel node biopsy (SNB) is required. The aim of this study was to determine the feasibility and accuracy of Immunohistochemistry (IHC)-stained touch imprints in detecting metastatic axillary nodes intraoperatively.
MATERIAL AND METHODS: Four hundred and thirty-two axillary nodes from 52 patients (23 axillary node clearance (ANC), 15 ANS and 14 SNB) were bisected, imprinted and stained with anti-cytokeratin 19 IHC. Results were compared with those of routine haematoxylin and eosin (H&E)-stained sections.
RESULTS: IHC imprints detected 32 positive nodes from 12 patients. H&E sections detected 31 positive nodes from 11 patients. IHC imprints missed metastases in three nodes and missed the diagnosis of positive axillae in two patients. H&E missed metastases in four nodes and missed the diagnosis of positive axillae in 3 patients. On a node-basis, sensitivities were 91.4 and 88.5%, negative predictive values (NPV) were 99.2 and 99.0% and overall accuracies were 99.3 and 99.1% for IHC imprints and H&E sections, respectively. On a patient-basis, sensitivities were 85.7 and 78.5%, NPVs were 95.2 and 93.1% and overall accuracies were 96.1 and 94.2% for IHC imprints and H&E sections respectively. There were no false positives. Interpretation of the results by a non-histopathologist was concordant with that of a histopathologist. Results might be obtained within 30-45 min depending on the number of examined nodes.
CONCLUSION: Intraoperative IHC staining of touch imprints of axillary sentinel nodes is feasible and is a reliable method for evaluating axillary nodes. Slides can be reliably interpreted by a trained non-histopathologist.