Accuracy and Limitations of Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy in Breast Cancer Patients with Positive Nodes.

Background: Axillary surgical management in patients with node-positive breast cancer at the time of diagnosis converted to negative nodes through neoadjuvant chemotherapy (NAC) remains unclear. Removal of more than two sentinel nodes (SLNs) in these patients may decrease the false negative rate (FNR) of sentinel lymph node biopsies (SLNBs). We aim to analyse the detection rate (DR) and the FNR of SLNB assessment according to the number of SLNs removed. Methods: A retrospective study was performed from October 2012 to December 2018. Patients with invasive breast cancer who had a clinically node-positive disease at diagnosis and with a complete axillary response after neoadjuvant chemotherapy were selected. Patients included underwent SLNB and axillary lymph node dissection (ALND) after NAC. The SLN was considered positive if any residual disease was detected. Descriptive statistics were used to describe the clinicopathologic features and the results of SLNB and ALND. The DR of SLNB was defined as the number of patients with successful identification of SLN. Presence of residual disease in ALND and negative SLN was considered false negative. Results: A total of 368 patients with invasive breast cancer who underwent surgery after complete NAC were studied. Of them, 85 patients met the eligibility criteria and were enrolled in the study. The mean age at diagnosis was 50.8 years. Systematic lymphadenectomy was performed in all patients, with an average of 10 lymph nodes removed. The DR of SLNB was 92.9%, and the FNR was 19.1. The median number of SLNs removed was 3, and at least, three SLNs were obtained in 42 patients (53.2%). When at least three sentinel nodes were removed, the FNR decreased to 8.7%. Conclusions: In this cohort, the SLN assessment was associated with an adequate DR and a high FNR. Removing three or more SLNs decreased the FNR from 19.1% to 8.7%. Complementary approaches may be considered for axillary lymph node staging after neoadjuvant chemotherapy. The study was approved by our institution's ethics committee (Instituto de Investigacion Sanitaria Hospital 12 de Octubre (imas12), Universidad Complutense de Madrid, Madrid, Spain) (https://clinicaltrials.gov/ct2/show/NCEI:20/0048).

Feasibility of targeted axillary dissection for de-escalation of surgical treatment after neoadjuvant chemotherapy in breast cancer.

BACKGROUND: Targeted axillary dissection, which combines sentinel lymph node biopsy with removal of the proven involved node noted during the staging process, has been shown to improve axillary staging and decrease false negative rates after neoadjuvant chemotherapy in patients with breast cancer. OBJECTIVE(S): The main goal of this study was to assess the ability to identify and remove the clipped node and the false negative rate of targeted axillary dissection. METHODS: We performed a prospective study among patients with biopsy-confirmed nodal metastases who received neoadjuvant chemotherapy. A clip was placed on the sample node prior systemic therapy. After neoadjuvant chemotherapy, all patients underwent sentinel lymph node biopsy (dual tracer), localization and excision of the clipped node and axillary lymph node dissection. The clipped node was preoperatively localized in all cases placing an iodine-125 seed guided by ultrasound. The pathology of the sentinel nodes and clipped node was compared with other nodes. RESULTS: A total of 455 patients with invasive breast cancer were studied. Of the 148 patients with NAC, 32 met the eligibility criteria and were enrolled in the study. Mean age at diagnosis was 52.3 years. Systematic lymphadenectomy was performed in all patients, with an average of 14.3 lymph nodes removed. Detection rate of the clipped node alone was 96.9%, and 100% for targeted axillary dissection. Ability of clipped node alone to predict nodal status showed a FNR of 10,5% while SLNB alone performed by dual tracer and targeted axillary dissection, showed FNRs of 5.3% and 5.0%, respectively. Sentinel lymph nodes matched clipped node in 23 patients (74.2%). CONCLUSION (S): In node positive breast cancer patients, targeted axillary dissection is a reliably approach for axillary staging after neoadjuvant chemotherapy. The preoperative location of the clipped node is mandatory to increase the detection rate and optimize the results of the technique.