Accuracy of intraoperative touch imprint cytologic analysis of sentinel lymph nodes in breast cancer

Background Eliminating full axillary dissection (AD) in the face of negative sentinel lymph nodes (SLN) has become increasingly popular. We sought to evaluate the accuracy of intraoperative touch imprint cytology in detecting clinically significant metastatic involvement of the SLN. Methods Retrospective review of intraoperative cytology and final hematoxylin-eosin stain evaluation of sentinel nodes examined in a community hospital from 1997 to 2002. Results During that period 1,585 patients underwent axillary dissection; 380 had SLN identification with 142 patients undergoing intraoperative cytologic evaluation of 446 SLNs. Fourteen patients with negative intraoperative cytology had involvement of a SLN on final hematoxylin-eosin examination, for a sensitivity of 75%, specificity of 100%, negative predictive value of 95%, and a false negative rate of 4.9%. In all but 1 case the metastasis was microscopic and measured 2 mm or less. Seven patients went on to completion axillary dissection (50%) with no additional nodal involvement found. Conclusions Intraoperative touch imprint cytology is accurate in predicting clinically significant SLN pathology. Although the false negative rate in this series was 4.9%, in all but 1 case it represented micrometastatic disease that may not necessarily require completion axillary dissection.