Is the intraoperative frozen section analysis of sentinel lymph nodes necessary in clinically negative node breast cancer?

PURPOSE: Although metastasis occurs in 1 or 2 sentinel lymph nodes (SLNs), axillary lymph node dissection (ALND) has been widely not performed. For axillary staging and management, the necessity of intraoperative frozen section analysis of SLN has been controversial. The aim of this study is to evaluate the validity and benefit of SLN analysis by permanent section alone in clinically negative lymph node breast cancer patients. METHODS: We conducted a retrospective study of 283 cases with negative node clinical findings between July 2018 and August 2019 in Samsung Medical Center. Clinical nodal stage was evaluated by physical examination, breast ultrasonography, breast magnetic resonance imaging, and chest computerized tomography. The cases were divided into 2 groups; the permanent group had 151 cases (53.4%) and the frozen group had 132 cases (46.6%). We retrospectively analyzed the differences in the number of metastatic lymph nodes and rates of performed ALND between the 2 groups. RESULTS: Baseline and clinicopathologic characteristics between the 2 groups were well balanced. Three cases in the permanent group and 6 cases in the frozen group underwent additional or immediate ALND. The rates of ALND between the 2 groups were not significantly different (P = 0.312). The cased of 78.9% and 89.5% with metastatic lymph nodes in permanent and frozen groups were in the pathologic N1 stage, respectively. CONCLUSION: SLNs analysis by permanent section alone may be performed in clinically negative axillary node breast cancer patients. Our findings can help to avoid unnecessary intraoperative frozen section analysis.