Another meta-analysis of 1,353 patients undergoing axillary lymph node biopsy to detect metastases showed that both CNB and FNA procedures performed well, with sensitivities of 74% and 88%, respectively, and a specificity of 100% for both procedures. Complication rates with US-guided biopsies were low, although slightly higher for CNB when compared with FNA (7% versus 1%, respectively), and most commonly included pain, hematoma, and bruising [142]. Some centers place a clip in the biopsied positive axillary node before treatment so that it can be surgically excised along with the sentinel node(s) after completion of the NAC; this procedure is sometimes referred to as targeted axillary dissection [138]. US-guided localization of the clipped lymph node can be performed preoperatively [139]. Excising the clipped lymph node and SLNs decreases the false-negative rate of SLNB [26]. In a study of 31 patients, 11 patients had residual axillary disease, and, in all cases, the clipped lymph node was positive [141]. In a prospective study of 23 patients with clipped axillary metastases before NAC, the surgeon retrieved the clipped node in 22 cases, and the SLN was retrieved in only 19. The clipped node was the SLN in only 14 cases (61%). The NPV was 100% for removal of clipped and sentinel nodes but only 85% for SLN removal alone [119]. Overall, US-guided biopsy offers a minimally invasive option to obtain histopathologic proof of axillary nodal involvement for suspicious findings, although a negative biopsy does not reliably exclude metastatic disease, and therefore surgical pathology remains the reference standard. When US-guided biopsy confirms metastatic disease in pathologic-appearing nodes, it can obviate the need for pretreatment sentinel node biopsy because the completion of axillary surgery is typically performed after therapy [2,117].
Monitoring Response to Neoadjuvant Systemic Therapy for Breast Cancer. Another meta-analysis of 1,353 patients undergoing axillary lymph node biopsy to detect metastases showed that both CNB and FNA procedures performed well, with sensitivities of 74% and 88%, respectively, and a specificity of 100% for both procedures. Complication rates with US-guided biopsies were low, although slightly higher for CNB when compared with FNA (7% versus 1%, respectively), and most commonly included pain, hematoma, and bruising [142]. Some centers place a clip in the biopsied positive axillary node before treatment so that it can be surgically excised along with the sentinel node(s) after completion of the NAC; this procedure is sometimes referred to as targeted axillary dissection [138]. US-guided localization of the clipped lymph node can be performed preoperatively [139]. Excising the clipped lymph node and SLNs decreases the false-negative rate of SLNB [26]. In a study of 31 patients, 11 patients had residual axillary disease, and, in all cases, the clipped lymph node was positive [141]. In a prospective study of 23 patients with clipped axillary metastases before NAC, the surgeon retrieved the clipped node in 22 cases, and the SLN was retrieved in only 19. The clipped node was the SLN in only 14 cases (61%). The NPV was 100% for removal of clipped and sentinel nodes but only 85% for SLN removal alone [119]. Overall, US-guided biopsy offers a minimally invasive option to obtain histopathologic proof of axillary nodal involvement for suspicious findings, although a negative biopsy does not reliably exclude metastatic disease, and therefore surgical pathology remains the reference standard. When US-guided biopsy confirms metastatic disease in pathologic-appearing nodes, it can obviate the need for pretreatment sentinel node biopsy because the completion of axillary surgery is typically performed after therapy [2,117].