Abstract P2-18-03: Feasibility of sentinel node biopsy following neoadjuvant chemotherapy in cytology-proven node positive breast cancer before chemotherapy
Authors: Enokido K , Watanabe C , Nakamura S , Ogiya A , Osako T , Akiyama F , Horio A , Iwata H , Ohno S , Kojima Y , Tsugawa K , Motomura K , Hayashi N , Yamauchi H , Sato N 
Published: August 2014

Abstract
BACKGROUND: Sentinel node biopsy (SNB) for the node negative breast cancer is standard treatment as an accurate assessment of axillary lymph node status; however, axillary node dissection is a standard procedure for the node positive breast cancer. Neoadjuvant chemotherapy (NAC) has become the standard of care for patients with locally advanced breast cancer. It is reported that 40% of node positive disease convert to node negative after NAC. It remains controversial whether SLB could be applied to patients who present with node-positive disease before neoadjuvant chemotherapy. In this study, we evaluated the accuracy of SNB following NAC in breast cancer patients presenting with cytology-proven axillary node metastasis before chemotherapy.
METHODS: A multicenter prospective study was performed from September 2011 to April 2013 in 101 breast cancer patients with positive axillary nodes, proven by ultrasound-guided fine-needle aspiration at initial diagnosis (T1-3, N1, M0). After the confirmation of patients as clinically node-negative by preoperative imaging following NAC, all patients underwent breast surgery, with SNB and complete axillary lymph node dissection. The sentinel nodes were examined by hematoxylin-eosin staining, immunohistochemical analysis or one-step nucleic acid amplification assay (OSNA).The false negative rate and detection rate were analyzed.
RESULTS: Among the 101 patients analyzed, all cases presented with invasive ductal carcinoma. with a mean tumor size of 3.4cm. Thirty-six cases were hormone receptor (HR) positive and HER2 negative (Lum), 14 cases were HR positive and HER2 positive (Triple-Positive), 27 cases were positive for HER2 (HER2-enriched), and 24 cases were Triple-Negative. After neoadjuvant chemotherapy, a complete clinical response in the primary tumor was seen in 24.8%(25/101), a partial response in 66.3%(67/101), and no response in 7.9%(8/101). Pathological complete response of primary tumor was 39.6%. The pathological complete nodal response rate was 42.2%. The sentinel lymph node could be identified in 91 of 101 cases (90.1%); 88.9% (32/36) of patients with Lum, 100%(14/14)of those with Triple-Positive, 85.2% (23/27) of those with HER2-enriched, and 91.7% (22/24)% of those with Triple-Negative breast cancer subtype. The false negative rate was 12.7%; 35.7 (5/14) for Lum, 0% (0/8) for Triple-Positive, 5.0% (1/20) for HER2-enriched, and 7.7% (1/13) for Triple-Negative subtype (P = 0.03).
CONCLUSION: SNB following NAC in patients with node-positive breast cancer was found to be technically feasible, but is not recommended for the Lum subtype. However, it might be safely considered in selected patients, those with Triple-Positive, HER2-enrich and Triple-Negative subtype breast cancers.
Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-03.