Impact of axillary ultrasound (AUS) on axillary dissection in breast conserving surgery (BCS)

Background and Objectives Preoperative axillary ultrasound (AUS) in clinically node-negative patients may increase axillary lymph node dissection (ALND) in ACoSOG Z0011-eligible patients. We hypothesize that AUS identifies operative axillary disease (>3 positive nodes) in women undergoing breast conserving surgery (BCS). Methods After IRB approval, a retrospective review of female breast cancer patients was performed; patients with clinical T1/T2 tumors undergoing BCS were included. Clinical, radiologic, and pathologic data were collected. Results Of 139 eligible subjects, 119/139 (86%) had nonpalpable axillary nodes. 47/119 patients (40%) had abnormal AUS and 15/47 (32%) had a positive FNA. Fourteen had ALND;10/14 (71%) had >3 positive nodes. 6/32 (18%) with abnormal AUS but FNA negative were sentinel lymph node (SLN) positive. Of 72 normal AUS, 15 (22%) were SLN positive; 9/15 (60%) had ALND; 1 (11%) had >3 positive nodes. When evaluating for >3 positive nodes, AUS plus FNA had a sensitivity of 91%, specificity of 95%, NPV of 99%, and PPV of 71%. Conclusions AUS/FNA has a high NPV for axillary metastasis and remarkable sensitivity for three or more positive axillary nodes, therefore AUS-identified metastasis should be treated as clinically node-positive disease, and is appropriate even in patients planning breast conserving surgery.