Correlation between outcome and extent of residual disease in the sentinel node after neoadjuvant chemotherapy in clinically fine-needle proven node-positive breast cancer patients

Background: Whether the extent of residual disease in the sentinel lymph node (SLN) after neoadjuvant chemotherapy (NAC) influences the prognosis in clinically node-positive breast cancer (BC) patients remains to be ascertained. Methods: One hundred and thirty-four consecutive cNthorn/BC-patients received NAC followed by SLN biopsy and axillary lymph node dissection. Cumulative incidence of overall (OS) and disease-free (DFS) survival, BC-related recurrences and death from BC were assessed using the Kaplan-Meier method both in the whole patient population and according to the SLN status. The log rank test was used for comparisons between groups. Results: The SLN was identified in 123/134 (91.8%) patients and was positive in 98/123 (79.7%) patients. Sixty-five of them (66.3%) had other axillary nodes involved. SLN sensitivity and false-negative rate were 88.0% and 2.0%, Median follow-up was 10.2 years. Ten-year cumulative incidence of axillary, breast and distant recurrences, and death from BC were 6.5%, 11.9%, 33.4% and 31.3%, respectively. Ten-year OS and DFS were 67.3% and 55.9%. When stratified by SLN status, 10-year cumulative incidence of BC-related and loco-regional events, and death from BC were similar between disease-free SLN and micrometastatic SLN subgroups (28.9% vs 30.2%, p = 0.954; 21.6% vs 13.4%, p = 0.840; 12.9 vs 24.5%, p=0.494). Likewise, 10year OS and DFS were comparable (80.0% vs 75.5%, p=0.975 and 68.0% vs 69.8, p=0.836). Both OS and DFS were lower in patients presenting a macrometastatic SLN (60.2% and 47.5%). Conclusion: Outcome of patients with micrometastatic SLN was similar to that of patients with diseasefree SLN, which was more favorable as compared to that of patients with macrometastatic SLN. (C) 2021 Published by Elsevier Ltd.