Accuracy of Imprint Cytology for Intraoperative Diagnosis of Sentinel Node Metastases in Breast Cancer

Abstract

The aim of this study was to determine the accuracy of imprint cytology for the intraoperative diagnosis of sentinel node metastases in patients with breast cancer. Accurate intraoperative diagnosis of sentinel node metastases enables the selection of patients who need axillary lymph node dissection during the same operation. This study included 631 patients with clinical T1 breast cancer with clinically negative nodes. Sentinel nodes were serially sectioned at 2-mm intervals. Imprint cytologic samples were made from all cut surfaces and stained with Papanicolaou staining. Patients with positive sentinel nodes underwent immediate axillary lymph node dissection. Those with negative sentinel nodes diagnosed by intraoperative imprint cytology, but positive by final pathologic results, underwent subsequent axillary lymph node dissection. The results of imprint cytology were compared with the final pathologic results using hematoxylin and eosin staining and immunohistochemistry. In 110 of 130 patients with positive sentinel nodes diagnosed by final pathology, imprint cytology of at least one sentinel node was positive. In 17 of 501 patients with tumor-negative sentinel nodes diagnosed by final pathology, imprint cytology of at least one sentinel node was positive. The sensitivity, specificity, and overall accuracy of imprint cytology for the diagnosis of sentinel node metastases were 84.6%, 96.6%, and 94.1%, respectively. Only 20 (3.2%) patients required a second axillary operation in the present study. Intraoperative imprint cytology is a useful method for evaluating sentinel node metastasis in patients with breast cancer.