Does use of axillary ultrasound in clinically node-negative patients receiving neo-adjuvant systemic therapy for breast cancer lead to surgical overtreatment?

Increased use of neo-adjuvant chemotherapy (NAC) for breast cancer has raised uncertainty regarding staging of the axilla, particularly for patients with a clinically negative axillary physical examination (PE). We sought to determine whether axillary ultrasound (AUS) prior to NAC to identify occult nodal disease is beneficial in patients with a clinically negative examination by evaluating the difference in nodal burden on final pathology in those with abnormal vs normal AUS. A retrospective review of an institutional cancer registry identified patients who underwent NAC for breast cancer and had a pretreatment AUS. Differences in the number of positive lymph nodes (PLN) in patients with a normal axillary PE and abnormal vs normal AUS prior to NAC were determined. A total of 120 patients who received NAC had a negative axillary PE prior to treatment. Fifty-three had an abnormal AUS and biopsy-proven lymph node (LN) involvement. In patients with an abnormal AUS, median number of PLNs at surgery was 1 vs 0 for those with a normal AUS (mean difference of 2.12, P < .0001). Of those patients with an abnormal AUS and biopsy-proven LN involvement, 87% underwent axillary lymph node dissection (ALND) and nearly half had no PLN on final pathology (N = 23, 43%). Patients with a clinically negative axilla and an abnormal AUS were more likely to have PLN at the time of surgery. However, almost half of those patients had no residual LN involvement. Routine AUS prior to NAC may lead to more extensive surgical management of the axilla.