Survival and inferential analysis in patients with locally advanced breast cancer treated with neoadjuvant chemotherapy and subsequent sentinel lymph node biopsy: prospective single-center study

Background: The lymph node staging is the major prognostic factor in breast cancer patients. Sentinel lymph node biopsy (SLNB) allows an exactly axillar staging in patients with early disease, but not in locally advance breast cancer (LABC). Our aim was to study, the feasibility and accuracy of the SLNB technique with and without axillar lymphadenectomy (LDN) and with lymph node clipping after neoadjuvant chemotherapy (NAC), in patients with LABC. Patients and methods: Patients diagnosed with LABC, scheduled for NAC and subsequent surgery and SLNB. Subsequently the patients were scheduled for adjuvant chemotherapy/hormonotherapy and radiotherapy according with the postsurgical results. Main end points were overall survival (OS) disease-free survival (DFS), mortality, SLNB identification rate (IR), sensitivity, false negative rate (FNR) of SLNB versus LDN, negative predictive value (NPV) and overall accuracy. Results: Our IR with different techniques was between 89.9 and 100%. OS was between 89 and 97%. DFS was between 89.8 and 96.8%. Sensitivity was between 75 and 100%. NPV was between 89.6 and 100%. FNR was between 0 and 25%; and accuracy was between 66 and 72%. We found that survival was lower (p < 0.05) in patients with triple negative and Luminal B/HER2 intrinsic subtype; with progression or major partial response in Magnetic Resonance Imaging (MRI) results at the end of NAC and in patients with BRCA1/2 mutation. Conclusions: Our study presents excellent results of SLNB alone in patients with LABC with complete nodal response with an OS and DFS > 95%. The FNR is very high in partial responders, so we cannot recommend the SLNB alone in LABC. We recommend, in cN+ patients, axillar clipping, SLNB and LDN because in more than 50% of the patients with axillar clipping, this was not found, and because in 36% of the patients with negative LDN, the SLN (Sentinel Lymph Node) obtained was the only positive node, so these techniques together decrease the FNR and improve the node staging, OS and DFS. This study is the first prospective study that assess OS and DFS in patients with LABC, all submitted to SLNB.