The sensitivity and specificity of sentinel lymph node biopsy for breast cancer at Baylor University Medical Center at Dallas: a retrospective review of 488 cases

Sentinel lymph node (SLN) biopsy has become the standard of care for breast carcinoma management, as it precludes the negative morbid effects—including decreased shoulder range of motion, lymphedema, and paresthesias—of unnecessary axillary lymph node dissection. However, the method of pathologic evaluation of the lymph node has been scrutinized to obtain the greatest sensitivity, specificity, and negative predictive value, ultimately for the benefit of the patient. This retrospective study analyzed 488 biopsies completed by two surgeons and read by multiple pathologists affiliated with Pathologists Biomedical Laboratories. When metastatic disease was not grossly obvious, analysis of the SLN began with touch imprint cytology and, if necessary, a frozen section analysis. On the subsequent day, three levels of the SLN were analyzed with hematoxylin and eosin stain and immunohistochemistry with cytokeratin AE1-3 and the appropriate control. Touch imprint cytology and/or frozen section analysis (where applicable) correctly identified 78 of 89 macrometastases, with a sensitivity of 88%, specificity of 100%, and negative predictive value of 97%. Sensitivity was 72% for micrometastases and 60% for isolated tumor cells, each with 100% specificity. In conclusion, the sensitivity and specificity of SLN biopsy at our institution compares with the higher end of percentages reported in the literature.