Sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with cytologically proven node-positive breast cancer at diagnosis

Background: The performance of sentinel lymph node biopsy (SLNB) after neoadjuvant chemotherapy (NCT) was investigated in patients with locally advanced breast cancer (LABC). Methods: After NCT of 178 patients with cytology-proven axillary/supraclavicular nodes metastasis at the time of diagnosis, SLNB using radioisotope was performed including completion node dissection between 2008 and 2011. The detection rate, sensitivity, false negative rate (FNR), negative predictive value (NPV) and accuracy of SLNB were analyzed. Results: SLNB was successfully performed in 169 (94.9 %) patients. Tumor nonresponse and extensive residual nodal disease were found to be significantly associated with detection failure of sentinel nodes. Sensitivity, FNR, NPV, and accuracy of SLNB were 78.0, 22.0, 75.8, and 87.0 %, respectively, and a greater number of retrieved SLNs increased all four of these performance measures. Conversion to node-negative disease was achieved in 69 (40.8 %) patients: 24 % of patients with the luminal A subtype, 51.6 % of patients with the luminal B, 51.7 % of patients with the HER2-enriched, and 58.5 % of patients with the triple-negative breast cancer (TNBC) subtype. Luminal B, HER2-enriched, and TNBC subtypes showed comparable responses to NCT; however, the TNBC subtype had a significantly better FNR and accuracy. Conclusions: SLNB was found to be technically feasible, but its routine use was not recommended for LABCs after NCT. However, acceptable performance was noted for locally advanced TNBCs, and thus SLNB might be safely considered in these selected patients.