Dual role of intraoperative ultrasound in axillary surgery: enhanced detection and surgical de-escalation in breast cancer

Intraoperative ultrasound (IO-USG) may optimize axillary management in breast cancer surgery. This study evaluated IO-USG’s dual role in preventing unnecessary axillary lymph node dissection (ALND) and identifying additional nodal metastases missed by sentinel lymph node biopsy (SLNB). This retrospective cohort study included 314 consecutive patients with invasive breast cancer who underwent SLNB with IO-USG evaluation between January 2019 and December 2023. IO-USG was performed after SLNB to identify suspicious non-sentinel nodes. Patients were categorized into SLNB-only, targeted axillary dissection (TAD), or ALND based on combined SLNB and IO-USG findings. Of 314 patients, 113 (36%) received neoadjuvant chemotherapy and 201 (64%) underwent upfront surgery. Final surgical management comprised SLNB-only in 244 (77.7%), TAD in 46 (14.7%), and ALND in 24 (7.6%) patients. Among 89 SLNB-positive patients, 68 (76.4%) avoided ALND through IO-USG guidance. IO-USG identified additional axillary metastases in 4 of 225 SLNB-negative patients (1.8%). Molecular subtype analysis revealed no IO-USG positivity in triple-negative cases (0/25), while HR+/HER2- tumors comprised 82.6% of IO-USG-positive cases. At a median follow-up of 33.2 months, no axillary recurrences occurred. IO-USG may support personalized axillary management, helping avoid ALND in 76.4% of node-positive patients while identifying additional axillary metastases in 1.8% of SLNB-negative cases. As a complementary technique to standard SLNB, it appears to provide selective utility based on tumor biology. Not applicable.