Correlation between clinical nodal status and sentinel lymph node biopsy false negative rate after neoadjuvant chemotherapy

Background Neoadjuvant chemotherapy (NAC) is the standard treatment for locally advanced breast cancer. It is now being used to treat operable breast cancer to facilitate breast-conserving surgery, but the accuracy of sentinel lymph node biopsy (SLNB) in breast cancer patients receiving NAC remains open to considerable debate. Methods We enrolled 96 patients with stage II-III breast cancer who received NAC from January 2001 to July 2010. All patients underwent breast surgery and SLNB, followed immediately by complete axillary lymph node dissection (ALND). Sentinel lymph nodes were detected with blue dye and radiocolloid injected intradermally just above the tumor and then evaluated with hematoxylin and eosin and immunohistochemical staining. Results The overall identification rate for SLNB was 87.5 % (84/96); the false negative rate (FNR) was 24.5 % (12/49); and the accuracy rate was 85.7 % (72/84). The FNR was significantly lower in clinically node-negative patients than in node-positive patients before NAC (5.5 % vs. 35.5 %; p = 0.001). Accuracy was also significantly higher in clinically node-negative patients than in nodepositive patients before NAC (97.2 % vs. 77.1 %; p = 0.009). The FNR was 27.3 % among 46 clinically nodepositive patients before NAC who were clinically nodenegative after NAC. Among 12 patients with a complete tumor response (CR), the FNR was 0 %, compared with 26.1 % for 83 patients with a partial response and stable disease (p = 0.404). Conclusions Although associated with a high FNR after NAC, SLNB would have successfully replaced ALND in clinically node-negative patients before NAC and in patients with a CR after NAC.