Outcomes of Sentinel Node Biopsy for Women with Breast Cancer After Neoadjuvant Therapy: Systematic Review and Meta-Analysis of Real-World Data

Background: Evidence on the accuracy of sentinel lymph node biopsy (SLNB) after neoadjuvant therapy (NAT) for patients with breast cancer is inconclusive. This study reviewed the real-world data to determine the acceptability of SLNB after NAT. Methods: The study searched for articles in the PubMed, EMBASE, and Cochrane Library databases. The primary outcomes were the identification rate for sentinel lymph nodes (SLNs) and the false-negative rate (FNR) for SLNB. The study also evaluated the FNR in subgroups defined by tumor stage, nodal stage, hormone receptor status, human epidermal growth factor receptor-2 status, tumor response, mapping technique, and number of SLNs removed. Results: The study retrieved 61 prospective and 18 retrospective studies with 10,680 initially cN± patients. The pooled estimate of the identification rate was 0.906 (95 % confidence interval [CI], 0.891–0.922), and the pooled FNR was 0.118 (95 % CI, 0.103–0.133). In subgroup analysis, the FNR was significantly higher for the patients with estrogen receptor (ER)-negative status and fewer than three SLNs removed. The FNR did not differ significantly between the patients with and those without complete tumor response. Among the patients with initial clinical negative axillary lymph nodes, the incidence of node metastasis was 26.8 % (275/1041) after NAT. Conclusion: Real-world evidence indicates that the FNR of SLNB after NAT in breast cancer is 11.8 %, exceeding only slightly the commonly adopted threshold of 10 %. The FNR is significantly higher for patients with ER-negative status and removal of fewer than three SLNs. Using a dual tracer and removing at least three SLNs may increase the accuracy of SLNB after NAT.