Sentinel node staging for breast cancer: Intraoperative molecular pathology overcomes conventional histologic sampling errors

BACKGROUND: When sentinel node dissection reveals breast cancer metastasis, completion axillary lymph node dissection is ideally performed during the same operation. Intraoperative histologic techniques have low and variable sensitivity. A new intraoperative molecular assay (GeneSearch BLN Assay; Veridex, LLC, Warren, NJ) was evaluated to determine its efficiency in identifying significant sentinel lymph node metastases (\u3e.2 mm). METHODS: Positive or negative BLN Assay results generated from fresh 2-mm node slabs were compared with results from conventional histologic evaluation of adjacent fixed tissue slabs. RESULTS: In a prospective study of 416 patients at 11 clinical sites, the assay detected 98% of metastases \u3e2 mm and 88% of metastasis greater \u3e.2 mm, results superior to frozen section. Micrometastases were less frequently detected (57%) and assay positive results in nodes found negative by histology were rare (4%). CONCLUSIONS: The BLN Assay is properly calibrated for use as a stand alone intraoperative molecular test