Comparison of intraoperative frozen section analysis of sentinel node with preoperative positron emission tomography in the diagnosis of axillary lymph node status in breast cancer patients

Background: Although axillary lymph node status is an important prognostic factor and axillary dissection is regarded as the gold standard for staging, it requires radical surgery which is accompanied by considerable postoperative problems such as lymphedema. This study was carried out to evaluate the diagnostic accuracy of preoperative positron emission tomography (PET) and intraoperative frozen biopsy of sentinel lymphadenectomy (SLND) in detecting axillary lymph node metastasis. Methods: We studied 18 patients who had preoperative PET and SLND for breast cancer in the Department of Surgery at Samsung Medical Center. They all had preoperative PET with a radiolabeled glucose analogue ([¹⁸F]FDG) to visualize primary tumors and metastatic nodes. Isosulphan blue dye was used for intraoperative SLND. Frozen and permanent biopsies were then compared after full axillary dissection. Results: In 18 cases, six had positive metastatic nodes in the permanent biopsy of full axillary dissection but were negative in three cases by preoperative PET. There was one false negative result by frozen biopsy of SLND which was later shown to be positive by permanent biopsy. The sensitivity and specificity of SLND and PET for detecting axillary node metastasis were 83, 100% and 50, 100%, respectively. Conclusion: Although both methods are good for axillary nodal status, the intraoperative frozen biopsy result of SLND was superior to preoperative PET in our preliminary study.