Cavalcante FP, Millen EC, Zerwes FP, Novita GG. Role of Axillary Surgery After Neoadjuvant Chemotherapy. JCO Glob Oncol. 2020 Feb;6:238-241.
“In a US study, associating selective localization and removal of clipped nodes with SLN dissection, known as targeted axillary dissection, reduced false-negative rates to approximately 2% compared with 4% with removal of the clipped lymph node alone.  However, patients are required to undergo two procedures: placement of the clip before systemic treatment and marking it to identify the lymph node during surgery. A retrospective analysis showed that in patients with clipped lymph nodes who were referred for preoperative marking, the clip failed to be identified in 20% of those patients, even when computed tomography was used, with the additional risk of the clip not being removed during surgery.  Therefore, the use of clips is controversial, because it is sometimes impossible to remove the clip alone. Despite the association between the number of lymph nodes and false-negative rates, there are still no convincing data regarding clinical outcome.”
Caudle AS, Yang WT, Krishnamurthy S, et al. Improved Axillary Evaluation Following Neoadjuvant Therapy for Patients With Node-Positive Breast Cancer Using Selective Evaluation of Clipped Nodes: Implementation of Targeted Axillary Dissection. J Clin Oncol. 2016 Apr 1;34(10):1072-8.
Results: Of 208 patients enrolled in this study, 191 underwent ALND, with residual disease identified in 120 (63%). The clipped node revealed metastases in 115 patients, resulting in an FNR of 4.2% (95% CI, 1.4 to 9.5) for the clipped node. In patients undergoing SLND and ALND (n = 118), the FNR was 10.1% (95% CI, 4.2 to 19.8), which included seven false-negative events in 69 patients with residual disease. Adding evaluation of the clipped node reduced the FNR to 1.4% (95% CI, 0.03 to 7.3; P = .03). The clipped node was not retrieved as an SLN in 23% (31 of 134) of patients, including six with negative SLNs but metastasis in the clipped node. TAD followed by ALND was performed in 85 patients, with an FNR of 2.0% (1 of 50; 95% CI, 0.05 to 10.7).
Conclusion: Marking nodes with biopsy-confirmed metastatic disease allows for selective removal and improves pathologic evaluation for residual nodal disease after chemotherapy.
Boughey JC, Suman VJ, Mittendorf EA, et al. Sentinel lymph node surgery after neoadjuvant chemotherapy in patients with node-positive breast cancer: the ACOSOG Z1071 (Alliance) clinical trial. JAMA. 2013 Oct 9;310(14):1455-61.
Results: Seven hundred fifty-six patients were enrolled from 136 institutions. Of 663 evaluable patients with cN1 disease, 649 underwent chemotherapy followed by both SLN surgery and ALND. A SLN could not be identified in 46 patients (7.1%). Only one SLN was excised in 78 patients (12.0%). Of the remaining 525 patients with 2 or more SLNs removed, no cancer was identified in the axillary lymph nodes of 215 patients yielding a pathological complete nodal response of 41.0% (95% CI: 36.7%–45.3%). In 39 patients, cancer was not identified in the SLNs but was found in lymph nodes obtained with ALND resulting in a FNR of 12.6% (90% Bayesian Credible Interval, 9.85%–16.05%).
Conclusions and Relevance: Among women with cN1 breast cancer receiving neoadjuvant chemotherapy who had 2 or more SLNs examined, the FNR was not found to be 10% or less. Given this FNR threshold, changes in approach and patient selection that result in greater sensitivity would be necessary to support the use of SLN surgery as an alternative to ALND.