Abstract P1-01-23: Increased Diagnostic Performance of Sentinel Lymph Node Biopsy Combined with Radiologic-pathologic Factors After Neoadjuvant Chemotherapy in Breast Cancer Patients with Cytologically Proven Node Metastasis at Diagnosis

Abstract

Abstract Background: It is undetermined whether sentinel lymph node biopsy (SLNB) is feasible and accurate for predicting final nodal status after neoadjuvant chemotherapy (NCT) in breast cancer patients with cytologically proven node metastasis at the time of diagnosis, although currently completion node dissection is a standard surgical procedure for the management of axilla. The aim of this study was to investigate diagnostic performance of SLNB after NCT in this subgroup. Methods: Of 374 patients with T1-T3 breast cancer who received NCT, 178 had initially biopsy proven axillary/supraclavicular metastasis and subsequently underwent SLNB using radioisotope alone followed by completion node dissection between 2008 and 2011. Detection rate, sensitivity, false negative rate (FNR), negative predictive value (NPV), and accuracy of SLNB were retrospectively analyzed and it was explored using regression analysis whether combination with clinicopathologic factors improved performance. Results: At initial presentation, 60.7% of patients were cT2 stage and 88.2% treated with concurrent or sequential anthracycline plus taxane preoperatively. SLNB was successfully performed in 169 (94.9%) patients. The mean number of sentinel and regional nodes retrieved was 2.1 ± 1.6 and 12.8 ± 6.3, respectively. Tumoral non-responder and extensive residual nodal disease were significantly associated with detection failure of SLNB. Conversion to node-negative disease was noted in 69 (40.8%) patients. Sensitivity, FNR, NPV, and accuracy of SLNB were 78.0%, 22.0%, 75.8%, and 87.0%, respectively and diagnostic performance increased when ≥ 3 sentinel nodes were evaluated. By logistic regression model, tumoral and nodal responder, absent lymphovascular invasion (LVI), estrogen receptor (ER)-negativity, and HER2-positivity were significantly associated with node-negative disease after NCT. Area under the receiver operating characteristic curve increased from 0.890 to 0.949 when considering radiologic-pathologic factors and FNR was the lowest value of 14.3% in 46 patients with tumoral responder, absent LVI, and ER-negative tumor. Conclusions: SLNB was technically feasible but solely showed higher FNR in this study. Improved diagnostic performance of SLNB combined with radiologic-pathologic characteristics suggests possible clinical value of SLNB after NCT in highly selected patients with node metastasis at diagnosis. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-23.