Less is more: The Role of preoperative ultrasound as a risk stratifying tool in identifying low volume axillary disease in breast cancer

OBJECTIVES: Axillary lymph node dissection (ALND) in early breast cancer causes lymphoedema in up to 20% of women and may be unnecessary in those with low axillary disease burden. This study evaluates whether preoperative axillary ultrasound (AUS) can stratify nodal burden preoperatively. METHODS: A retrospective single-centre observational study was conducted using records from January 2023-December 2024. Among 193 patients with abnormal AUS, those with negative axillary biopsy, neoadjuvant therapy, no surgery, or distant metastases were excluded. Data on AUS findings, tumour size, and postoperative nodal histology were collected. Differences between pN1 (<4 positive nodes on ALND) and pN2-3 (≥4 positive nodes on ALND) disease were analysed using non-parametric and categorical tests. RESULTS: Of 193 patients, 142 (73.6%) had positive axillary biopsies; 134 were included. Among these, 76 (56.7%) had 1-2 abnormal nodes on AUS. Of 77 evaluable cases, 33 (42.9%) had pN1 and 44 (57.1%) pN2-3 disease. The mean number of abnormal nodes was higher in pN2-3 (3.05 ± 1.85) than pN1 (1.52 ± 0.89; p = 0.0001). Tumour size was greater in pN2-3 (57.9 ± 33.7 mm) than pN1 (36.5 ± 24.3 mm; p = 0.0012). AUS performance: Sensitivity 87.1%, Specificity 55%, PPV 60%, NPV 84.6%, Accuracy 69%. CONCLUSION: AUS effectively identifies patients with low-volume axillary disease preoperatively supporting risk stratification. ADVANCES IN KNOWLEDGE: Axillary ultrasound findings, particularly abnormal node count, may contribute to preoperative stratification of nodal burden and support consistent triage when interpreted alongside tumour/pathology factors.