The Evolving Role of Marked Lymph Node Biopsy (MLNB) and Targeted Axillary Dissection (TAD) after Neoadjuvant Chemotherapy (NACT) for Node-Positive Breast Cancer: Systematic Review and Pooled Analysis

SIMPLE SUMMARY: The 5-year survival rate for patients with breast cancer, in whom disease has spread to local lymph nodes, is 85%. However, many live with the complications of surgery to remove the lymph nodes in the armpit thus impacting their quality of life. In recent years, new approaches have been developed to minimise surgery and reduce complications. The aim of this systematic review was to assess the feasibility and accuracy of two minimally invasive surgical procedures, Marked Lymph Node Biopsy and Targeted Axillary Dissection as an alternative to complete removal of the axillary lymph nodes after upfront chemotherapy in patients in whom cancer spread to the regional lymph nodes. Our findings confirm that these procedures can safely replace more radical surgery in women who have responded well to upfront drug treatment. Therefore, although further research to determine long-term outcomes is required, this review concludes that it is reasonable to offer such patients the option of less invasive surgery thus avoiding over treatment and enhancing quality of life. ABSTRACT: Targeted axillary dissection (TAD) is a new axillary staging technique that consists of the surgical removal of biopsy-proven positive axillary nodes, which are marked (marked lymph node biopsy (MLNB)) prior to neoadjuvant chemotherapy (NACT) in addition to the sentinel lymph node biopsy (SLNB). In a meta-analysis of more than 3000 patients, we previously reported a false-negative rate (FNR) of 13% using the SLNB alone in this setting. The aim of this systematic review and pooled analysis is to determine the FNR of MLNB alone and TAD (MLNB plus SLNB) compared with the gold standard of complete axillary lymph node dissection (cALND). The PubMed, Cochrane and Google Scholar databases were searched using MeSH-relevant terms and free words. A total of 9 studies of 366 patients that met the inclusion criteria evaluating the FNR of MLNB alone were included in the pooled analysis, yielding a pooled FNR of 6.28% (95% CI: 3.98–9.43). In 13 studies spanning 521 patients, the addition of SLNB to MLNB (TAD) was associated with a FNR of 5.18% (95% CI: 3.41–7.54), which was not significantly different from that of MLNB alone (p = 0.48). Data regarding the oncological safety of this approach were lacking. In a separate analysis of all published studies reporting successful identification and surgical retrieval of the MLN, we calculated a pooled success rate of 90.0% (95% CI: 85.1–95.1). The present pooled analysis demonstrates that the FNR associated with MLNB alone or combined with SLNB is acceptably low and both approaches are highly accurate in staging the axilla in patients with node-positive breast cancer after NACT. The SLNB adds minimal new information and therefore can be safely omitted from TAD. Further research to confirm the oncological safety of this de-escalation approach of axillary surgery is required. MLNB alone and TAD are associated with acceptably low FNRs and represent valid alternatives to cALND in patients with node-positive breast cancer after excellent response to NACT.