A prospective study comparing touch imprint cytology, frozen section analysis, and rapid cytokeratin immunostain for intraoperative evaluation of axillary sentinel lymph nodes in breast cancer

BACKGROUND: The intraoperative evaluation of axillary sentinel lymph nodes (SLNs) allows the surgeon to complete axillary dissection in 1 setting at the time of the primary breast surgery. However, to the authors' knowledge, there is no consensus regarding the optimal method for intraoperative evaluation of SLNs in breast cancer. The authors of this report prospectively compared touch imprint (TI) cytology with frozen section (FS) analysis and rapid cytokeratin immunostaining (RCI) of SLNs for the intraoperative evaluation of disease and compared the results with final pathologic examination (FP). METHODS: Patients with invasive breast carcinoma who were diagnosed with lymph node‐negative disease (based on preoperative clinical and sonographic evaluation with or without fine‐needle aspiration of the indeterminate lymph nodes) and who subsequently were scheduled for lymphatic mapping were eligible to participate in this prospective protocol. TI and FS analysis were performed on all SLNs, and the lymph nodes were stained by the hematoxylin and eosin (H&E) method. RCI was performed using the enhanced polymer 1‐step cytokeratin method. The results of TI, FS, RCI, TI plus FS, and FS plus RCI were compared with the results from FP, including 1 H&E stain and cytokeratin immunostain of the third level. RESULTS: One hundred patients with invasive mammary carcinoma were accrued to the study. Eighty‐five tumors were the ductal type, 8 tumors were lobular, 5 tumors were mixed ductal and lobular, 1 was an adenoid cystic tumor, and 1 tumor was metaplastic carcinoma. Seventy‐two tumors were staged clinically as T1N0M0, 25 tumors were staged as T2N0M0, and 3 tumors were staged as T3N0M0. Metastatic carcinoma was detected in the SLNs by 1 or more methods, including TI, FS, RCI, and FP, in 20 tumors, which included 12 macrometastases and 8 micrometastases. TI detected 8 of 12 macrometastases (67%), FS detected 12 of 12 macrometastases (100%), RCI detected 12 of 12 macrometastases (100%), and FP detected 12 of 12 macrometastases (100%). TI detected 1 of 8 micrometastases (13%), FS detected 3 of 8 micrometastases (38%), RCI detected 4 of 8 micrometastases (50%), and FP detected 6 of 8 micrometastases (75%). The sensitivities of TI, FS, RCI, TI plus FS, and FS plus RCI (with FP as the gold standard) were 50%, 72%, 78%, and 83%, respectively, and the sensitivities of the same intraoperative methods were 45%, 75%, 80%, and 85%, respectively, with detection of metastatic disease