Axillary tumour burden in women with one abnormal node on ultrasound compared to women with multiple abnormal nodes

Aim: To determine if the number of abnormal nodes seen on preoperative axillary ultrasound (AUS) is a predictor of the number of positive nodes at histology for women with needle-biopsy-proven positive nodes.

Materials and methods: This prospective multicentre cohort study included consecutive patients with early breast cancer who had needle-biopsy-proven positive nodes on AUS and underwent axillary lymph node dissection (ALND) between October 2015 and July 2016. The number of abnormal nodes at preoperative AUS was recorded by breast radiologists or radiographers.

Results: One hundred and twenty-three patients were included in the study. The median age of the women was 62 (range 30-93) years. Fifty-four of the 123 (44%) women had one abnormal node, whereas 69 (56%) had multiple abnormal nodes on AUS. Forty of the 123 (33%) women had two or fewer nodes with metastases at histology after ALND. Tumours ≤20 mm (p<0.001) and one abnormal node on AUS (p<0.001) were associated with two or fewer nodes with metastases at ALND. Both remained significant in logistic regression analysis. The likelihood of at least three metastases based on the combination of these two factors had 95% sensitivity (79 of 83), 35% specificity (14 of 40), a negative predictive value of 78% (14 of 18), and a positive predictive value of 75% (79 of 105).

Conclusion: Among women with needle-biopsy-proven positive nodes, around three in four women (78%) with an invasive tumour ≤2 cm and one abnormal node on AUS have two or fewer positive nodes at ALND. These women are overtreated by upfront ALND and can be offered sentinel node biopsy (SNB).