Prospective Comparison of Intraoperative Touch Imprint Cytology and Frozen Section Histology on Axillary Sentinel Lymph Nodes in Early Breast Cancer Patients

Introduction: Since the late 1970s, sentinel lymph node biopsy (SLNB) has been used for several solid malignancies to identify lymph node metastases. This procedure is associated with less surgical morbidity than complete lymphadenectomy. Recent evidence suggests that axillary lymphadenectomy is not required for breast sentinel nodes with micrometastases (≤2 mm). Current clinical management of sentinel nodes indicates that only macrometastases (>2 mm) should be detected intraoperatively. In Japan, an intraoperative histopathological frozen section (FS) method is used to identify lymph node metastases, but this method takes more than 30 min and requires complex techniques and expensive equipment. Touch imprint cytology (TIC) is an easier, less expensive, and faster method, but its sensitivity has been shown to be low. Objective: The purpose of this study was to determine if TIC is more useful than FS in identifying macrometastases in sentinel lymph nodes in preoperative node-negative breast cancer operations. Methods: A prospective review of 49 consecutive patients with node-negative breast cancer treated with SLNB and intraoperative TIC and FS between November 2017 and June 2019 was performed. TIC samples were stained using Papanicolaou and Diff-Quick stains. Results were compared with routine postoperative paraffin sections. Results: With TIC, the Papanicolaou stain took a mean of 12 min, and the Diff-Quick stain took a mean of 10 min. Results of both TIC stain methods were the same. In contrast, the FS method took a mean of 80 min (including the transfer of specimens to a different hospital with the necessary equipment). TIC confirmed macrometastases in 5 cases. All macrometastases were diagnosed equally by the 2 techniques. Both the sensitivity and specificity of TIC were 100% for detection of macrometastases. Conclusion: TIC of SLNB for breast cancer is an easy and useful method for the detection of macrometastases of breast sentinel nodes.