Does open biopsy before mastectomy affect the prevalence of so-called axillary lymph node micrometastases detected immunohistochemically

To determine the effect of a previous open biopsy on the presence of immunohistochemically detected micrometastases, particularly single cells, in axillary lymph nodes in patients with "node-negative" invasive breast carcinoma. Node-negative breast cancer patients were divided into group 1 (diagnostic frozen-section biopsy with immediate mastectomy and axillary dissection) and group 2 (open surgical biopsy with temporally delayed mastectomy and axillary dissection). Archival slides of lymph nodes were examined and new sections stained with hematoxylin-eosin and immunohistochemically with a cytokeratin cocktail to detect micrometastases. Four (12%) of 33 patients had unequivocal lymph node metastases on additional hematoxylin-eosin sections (3 cases) or review of original material (1 case). Immunohistochemical analysis contributed additional data in only 1 group 2 patient. In this case a single strongly keratin-positive sinus-based cell was detected in 1 lymph node. The study suggests that previous surgical biopsy of the breast does not increase the incidence of immunohistochemically detected keratin positive cells in axillary lymph nodes.