Omission of sentinel lymph node biopsy in early-stage breast cancer: ongoing trial at the P.A. Herzen Moscow Oncology Research Institute

Background. Sentinel lymph node biopsy (SLNB) is the standard of regional staging in early-stage breast cancer (BC). However, contemporary randomized trials (SOUND, INSEMA, NAUTILUS) demonstrate the feasibility of safe axillary surgical de-escalation in a defined subset of patients with clinically node-negative (cN0) disease. Given the low rate of axillary lymph node metastases and the limited sensitivity of SLNB, this procedure may represent overtreatment in a proportion of patients.

Aim. To evaluate the oncological safety and clinical impact of SLNB omission in patients with early-stage breast cancer and clinically intact axillary lymph nodes, and to define approaches to adjuvant therapy optimization in this cohort.

Materials and methods. A prospective randomized non-inferiority trial is being conducted at the P.A. Herzen Moscow Oncology Research Institute. Patients with early-stage BC (cTis–cT2, cN0) were randomized 1:1 to SLNB or SLNB omission. In patients with cT1c–T2 disease, intraoperative fine-needle aspiration biopsy of the sentinel lymph node was additionally performed using a fan-shaped technique. The primary endpoint is disease-free survival. Secondary endpoints include overall survival, distant metastasis-free survival, locoregional and axillary recurrence rates, and quality-of-life characteristics.

Results. The preliminary analysis included 151 patients. In the cT1a–b cohort assigned to SLNB omission, no lymph node metastases were identified. In the SLNB control group, metastases were detected in 12.5 % of patients, with involvement limited to no more than one lymph node in all cases. In the cT1c–T2 cohort, the metastatic involvement rate was 16.5 %. Intraoperative fine-needle aspiration biopsy of the sentinel lymph node demonstrated a sensitivity of 57.1 %, specificity of 100 %, positive predictive value of 100 %, and negative predictive value of 92.8 %. Favorable biological subtypes (luminal tumors) and low-to-intermediate histological grades predominated in the study population.

Conclusion. Preliminary findings suggest potential oncological safety of SLNB omission in carefully selected patients with early-stage breast cancer and cN0 status. Rigorous preoperative axillary assessment using imaging modalities is a prerequisite. Further patient recruitment and extended follow-up are required to enable definitive evaluation of long-term oncological outcomes and to refine criteria for axillary surgical de-escalation.