e12600 Background: Appropriate biopsy procedure for clinically positive (suspicious) lymph nodes (LN) plays a key role in accurate axillary staging of early breast cancer. Fine needle aspiration (FNA) is a recommended method for clinically suspicious nodes in the National Comprehensive Cancer Network (NCCN) guidelines. However, the false negative rate (FNR) of FNA remains too high. Therefore, it is valuable to explore an alternative and appropriate procedure in clinical practice. We conducted a retrospective review to compare the feasibility and diagnostic efficiency of using a novel procedure, the intraoperative ultrasound guided wire (IOUS-wire) localization biopsy with frozen section, to FNA for assessment of clinically positive nodes in patients with early breast cancer. Methods: Data on consecutive primary breast cancer patients with documented axillary ultrasound results who had clinically positive lymph nodes (cN1) between January 2015 and September 2023 either utilization of IOUS-wire localization or ultrasonography-guided fine-needle aspiration cytology (US-FNAC) for clinically positive lymph nodes were retrospectively analyzed. Sentinel lymph node biopsy (SLNB) was performed in patients with negative histopathological or cytological results. The false negative rate (FNR) of histopathology between two groups was calculated. Results: Eligible patients (n=198) referred to axillary biopsy by IOUS-wire localization biopsy(n=100) and US-FNAC(n=98) in this study. The FNR of clinically positive lymph nodes biopsy was 12.8 percent in the IOUS-wire localization group and 87.5 percent in the US-FNAC group.IOUS-wire failed in 5 patients. Among the remaining 32 successful identifications, 26 were IOUS-wire-node positive by intraoperative frozen section. 42 patients with additional lymph node metastases were found in FNAC-LN-negative patients by SLNB. The accuracy rate was respectively 95% and 57.1%. No significant difference was observed in complications and median number of SLNs harvested (5.3 versus 5.5; P=0.631) between the groups. Sufficient tissue samples can be obtained for intraoperative frozen pathology so the FNR is potentially reduced. In addition, the interval of waiting time for pathological results is reduced. Conclusions: Intraoperative US-guided wire localization biopsy is a feasible and alternative procedure compared to preoperative FNA for clinically node-positive patients with early breast cancer. This novel method is suitable for China's national conditions and should be further pursued as a potential biopsy method for evaluation of axillary node status in clinical practice.