How much does axillary ultrasound contribute in women undergoing breast-conserving surgery with no palpable axillary nodes?

Background: The primary objective was evaluation of axillary ultrasound (AxUS) in preoperative staging of patients with invasive carcinoma undergoing breast-conserving surgery.

Methods: This is a retrospective, observational cohort study of patients with clinically node-negative (cN0) biopsy-proven invasive breast carcinoma undergoing breast-conserving surgery between January 2011 and December 2014 who underwent AxUS with fine needle aspiration (FNA) biopsy of sonographically abnormal lymph nodes. Patient records were reviewed.

Results: A total of 713 cases were analysed. Four hundred and thirty-three patients underwent formal preoperative AxUS; 100 underwent biopsy for abnormal findings. Of these, 32 had positive FNA biopsy result and underwent level II axillary dissection (axillary lymph node dissection (ALND)). Thirty were T1-2 tumours with AxUS scan/FNA demonstrating sensitivity of 25.2%, specificity of 100%, positive predictive value of 100% and negative predictive value of 76.6%. Forty-six patients had a positive sentinel lymph node (SLN) biopsy and axillary dissection. 34.8% of T1 tumours, 47.8% of T2 tumours and 100% of T3 tumours had further positive nodes. The average number of nodes involved per axilla was 1.8 for the T1 group, 4.1 for the T2 group and 4.6 in the T3 group. Macrometastases were a more common finding than micrometastases for all T stages undergoing ALND. A suspicious preoperative AxUS result was significantly associated with positive SLN. Other risk factors for positive SLN biopsy were oestrogen receptor positivity and lymphovascular invasion.

Conclusion: AxUS identifies patients with high nodal burdens justifying immediate ALND. AxUS did not adversely affect women with histologically negative sentinel nodes. Three percent may have been overtreated.