The role of ultrasound-guided lymph node biopsy in axillary staging of invasive breast cancer in the post-ACOSOG Z0011 trial era.

Abstract

Axillary status in invasive breast cancer, established by sentinel lymph node biopsy (SLNB) or ultrasound-guided lymph node biopsy, is an important prognostic indicator. The ACOSOG Z0011 trial showed that axillary dissection may be redundant in selected sentinel node-positive patients, raising questions on the applicability of these conclusions on ultrasound positive patients. The purpose of this study was to evaluate potential differences in patient and tumor characteristics and survival between axillary node positive patients after ultrasound (US group) or sentinel lymph node procedure (SN group). Patients diagnosed with invasive breast cancer at the Máxima Medical Center between January 2006 and December 2011 were studied. In total, 302 node-positive cases were included: 139 and 163 cases in the US and SN groups, respectively. Patients in the US group were older at diagnosis (p<0.001), more often had palpable nodes (p<0.001), mastectomy (p<0.001), larger tumors (p<0.001), higher tumor grade (p=0.001), lymphovascular invasion (p=0.035), a positive Her2Neu (p=0.006), and a negative hormonal receptor status (p=0.003). Also, they were more likely to have more lymph nodes with macrometastases (p<0.001), extranodal extension (p<0.001), and involvement of level-III-lymph node (p<0.001). Finally, they showed a worse disease-free survival [hazard ratio (HR)=2.71; 95% confidence interval (CI)=1.49-4.92] and overall survival (HR=2.67; 95% CI=1.48-4.84) than the SN group. These results suggest that ultrasound-positive patients have less favorable disease characteristics and a worse prognosis than SN-positive patients. Therefore, we conclude that omitting an ALND is as yet only applicable, as concluded in the Z0011, in patients with a positive SLNB.