Evaluation of intraoperative scrape cytology for sentinel lymph node biopsy in patients with breast cancer.

The techniques for intraoperative evaluation of sentinel lymph nodes (SLNs) vary. The most common methods include frozen section, imprint cytology/touch preparation cytology, and scrape cytology (SC). The purpose of this study was to evaluate whether there is concordance between the intraoperative SC and the final pathology of SLNs in patients with breast cancer. From October 2001 to June 2005, sentinel lymph node biopsies were attempted in 181 patients with breast cancer using a combination of blue dye and radioisotope. A lymph node was considered an SLN when it was stained with blue dye, had a blue lymphatic afferent, had increased radioactivity, or was abnormal by palpation. SLNs were successfully identified in 180 patients, for an identification rate of 99.4%. Forty-five patients had positive SLNs. In 16 (35%) of those patients, the SLNs were negative intraoperatively by SC. All of the false negatives occurred in SLNs with micrometastases. Thus, SC is an excellent method for identifying macrometastases intraoperatively, but less successful for micrometastases.