Identification and resection of clipped node decreases the false-negative rate of sentinel lymph node surgery in patients presenting with node-positive breast cancer (T0-T4, N1-N2) Who receive neoadjuvant chemotherapy: Results from ACO SOG Z107 1 (Alliance)

Background: The American College of Surgeons Oncology Group Z1071 trial reported a false-negative rate (FNR) of 12.6% with sentinel lymph node (SLN) surgery after neoadjuvant chemotherapy in women presenting with node-positive breast cancer. One proposed method to decrease the FNR is clip placement in the positive node at initial diagnosis with confirmation of clipped node resection at surgery. Methods: Z1071 was a multi-institutional trial wherein women with clinical T0-T4,N1-N2,M0 breast cancer underwent SLN surgery and axillary dissection (ALND) after neoadjuvant chemotherapy. In cases with a clip placed in the node, the clip location at surgery (SLN or ALND) was evaluated. Results: A clip was placed at initial node biopsy in 203 patients. In the 170 (83.7%) patients with cN1 disease and at least 2 SLNs resected, clip location was confirmed in 141 cases. In 107 (75.9%) patients where the clipped node was within the SLN specimen, the FNR was 6.8% (confidence interval [CI]: 1.9%-16.5%). In 34 (24.1%) cases where the clipped node was in the ALND specimen, the FNR was 19.0% (CI: 5.4%-41.9%). In cases without a clip placed (n = 355) and in those where clipped node location was not confirmed at surgery (n = 29), the FNR was 13.4% and 14.3%, respectively. Conclusions: Clip placement at diagnosis of node-positive disease with removal of the clipped node during SLN surgery reduces the FNR of SLN surgery after neoadjuvant chemotherapy. Clip placement in the biopsy-proven node at diagnosis and evaluation of resected specimens for the clipped node should be considered when conducting SLN surgery in this setting.