Omitting the sentinel lymph node biopsy: a region's perspective following recommendations from the SOUND trial

Sentinel lymph node biopsy (SLNB) remains the standard of care for axillary staging in early breast cancer (BC). However, its associated morbidity has prompted interest in de-escalating axillary surgery. The SOUND and INSEMA trials demonstrated that patients with small tumours and negative preoperative axillary imaging could safely omit SLNB without compromising outcomes.

This multicentre retrospective study evaluated whether SLNB influenced treatment decisions in our region in patients aged 70 years and above with small, invasive BC (<2cm) and negative preoperative axillary imaging. This study included 426 patients at six hospital trusts across the Southwest UK between 2019 and 2023. Information on histology, imaging and treatment decisions was obtained from electronic records.

The median age was 77 years; 362 patients (85.0%) had ER-positive, HER2-negative disease. Of the 426 patients, only 25 had their treatment altered as a result of their SLNB (four patients had an axillary node clearance, 19 had radiotherapy to their axilla and the other two patients underwent further investigations, eg, staging computed tomography scans). Twelve patients with positive lymph nodes were offered chemotherapy, of which six declined. The aggregate positive predictive value was 94.1% (95% CI 91.9%-96.4%), which was generally consistent across receptor subgroups.

Our data are concordant with the SOUND trial, which suggests that SLNB could have been omitted safely in patients with early BC and negative preoperative imaging of the axilla; however, our data cannot confer safety. By implementing SLNB omission across our region we hope to reduce surgical morbidity while providing safe, evidence-based treatment.