Improved detection of metastases to lymph nodes and estrogen receptor determination.

We present a new method for detection of micrometastases to axillary lymph nodes and estrogen receptor determination. Cellular suspensions from primary infiltrating ductal breast carcinoma or level I axillary lymph nodes of patients who underwent mastectomies were obtained, by loosely grinding fresh tumors or lymph nodes through a grid and then transferring the matrix to a slide using cytocentrifugation. Tumor samples were analyzed for estrogen receptor status using an immunocytochemical kit and compared with the dextran-coated charcoal method. Thirty-eight of 48 correlated (20 were estrogen positive, and 18 were estrogen negative). Seven of 46 were estrogen positive while results from the dextran-coated charcoal method were estrogen negative. One of 46 was estrogen negative, while the results from the dextran-coated charcoal method were estrogen positive. Lymph node slide preparations were stained to detect tumor cells using antikeratin monoclonal antibodies. Three of 8 node-negative patients were found to have micrometastases. Four of 15 node-positive patients had additional nodes with tumor. Our method combines the advantages of serial sectioning and immunohistochemical staining.