PURPOSE: The steady move towards axillary conservatism in breast cancer is based on studies demonstrating that axillary node clearance affords no survival benefit in a subset of patients with a positive pre-operative axillary ultrasound (AUS). However, less attention has been paid to AUS-negative patients who receive sentinel node biopsy as standard. METHODS: Previously assembled systematic review data was reassessed to evaluate nodal burden amongst patients with breast cancer and a clinically and radiologically negative axilla. RESULTS: Pooled data from four cohort studies reporting pre-operative axillary ultrasound in 5139 patients with breast cancer show it has a negative predictive rate of 0.951 (95% confidence interval 0.941-0.960). CONCLUSIONS: Reconsidering the use of ultrasound in patients with early breast cancer and non-palpable axillae reveals that sentinel node biopsy itself may represent surgical over-treatment in patients with a negative axillary ultrasound. The implications of this on the future of surgical management of the axilla are discussed.