Reliability of Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy in Breast Cancer Patients

PURPOSE Sentinel lymph node biopsy (SLNB) is an accurate and effective means of axillary nodal staging in early breast cancer. However its indication after neoadjuvant chemotherapy (NAC) is under constant debate. The present study evaluates the reliability of SLNB in assessing axillary nodal status after NAC. METHODS Data from 281 patients who had received NAC and subsequent SLNB were reviewed. The identification and false negative rates of SLNB were determined and the clinicopathologic factors associated with false negative results were investigated using univariate analysis. RESULTS The identification rate of SLNB after NAC was 93.6% and the false negative rate was 10.4%. Hormone receptor status, especially progesterone receptor positivity, was significantly associated with false negative results. The accuracy of intraoperative frozen section examination of sentinel lymph nodes was 91.2%. CONCLUSION The identification rate of SLNB and the accuracy of intraoperative frozen section examination after NAC are comparable to the results without NAC in patients with early breast cancer. However considering the high false negative rates, general application of SLNB after NAC should be avoided. Patients with progesterone-positive tumors and non-triple-negative breast cancers may be a select group of patients in whom SLNB can be employed safely after NAC, but further studies are necessary.