While initially implemented for patients with inoperable breast cancers, the use of neoadjuvant chemotherapy (NAC) was broadened to allow women to become candidates for breast conserving surgery.1 Clinical trials have shown no statistically significant differences in disease-free survival (DFS) and overall survival (OS) between patients who received NAC compared with those who received postoperative chemotherapy.2 Despite the evidence supporting the safety of a less extensive breast operation after a significant response to NAC, it has been a challenge to change the management of the axilla for definitive nodal staging in these patients.The safety and efficacy of sentinel lymph node biopsy (SLNB) for axillary staging was confirmed in NSABP B-32, where this technique was shown to have equivalent OS, DFS, and regional control compared with axillary lymph node dissection (ALND) in clinically node-negative patients.3 This study, along with other large prospective trials, demonstrated low false negative rates (FNR) of \10 % with very low rates of axillary recurrence (1 %). 4 The feasibility and accuracy of SLNB following NAC has been illustrated in multiple studies, most notably in NSABP B-27. 5 In this study, the SLN identification rate was 85 % with a FNR of 8 % when dual tracer techniques were used. These findings, as well as those in other retrospective studies, have allowed surgeons to comfortably perform SLNB after NAC for patients with no evidence of axillary metastases prior to NAC. However, once metastatic disease was documented within the axilla prior to NAC, an ALND was the only form of nodal staging offered at the time of the definitive breast operation for the majority of patients. With the knowledge that NAC can decrease, if not completely diminish, tumor burden within the breast as well as the axilla, and that SLNB is feasible in this patient population, why have we been so reluctant to defer ALND in women who have been downstaged to clinically node negative following NAC? Three prospective studies have investigated the accuracy of SLNB after NAC in initially nodepositive patients and demonstrated variable FNRs; many were unacceptably high ([10 %) when the entire study population was included. [7][8][9] However, when patients with C3 SLNs were analyzed, the FNRs decreased to \10 % in most cases. With the suggested benefit of analyzing C3 SLNs, the differences in methodologies as well as a median number of 2 SLNs examined in these prospective trials, critics have questioned the feasibility of performing an accurate SLNB after NAC.In this manuscript, Mamtani et al. attempted to answer this question with a single-center, prospective analysis investigating the frequency with which node-positive patients meet criteria for SLNB, with low FNR, following NAC. From 2013 to 2015, they identified 195 patients with stage II-III, node-positive disease at presentation who received NAC and completed surgery by November 2015. Those with clinical T4 or N2/N3 disease were excluded, leaving 155 evaluable patients. Of the...