Abstract PD15-03: PD15-03 Incorporation of Repeated Core Needle Biopsy and Targeted Fine Needle Aspiration to Optimize Axillary Surgery After Neoadjuvant Chemotherapy in Node-positive Breast Cancer: A Prospective Feasibility Study

Abstract

Abstract Background: It is of substantial importance to tailor axillary surgery after neoadjuvant chemotherapy (NAC) based on tumor biology and response to treatment. This study aimed to determine the accuracy of repeated core needle biopsy (RCNB) in breast to predict nodal response after NAC. Methods: Eligible patients with clip insertment into pathologically-proven positive node underwent RCNB during NAC. Targeted fine needle aspiration (TFNA) of clipped lymph node (CLN) was performed in a subset of patients after NAC. All patients ultimately underwent axillary surgery. RCNB and TFNA results were compared with surgical pathology. Results: Data from 189 eligible patients were analyzed. The overall axillary pCR was 57.1%. The false-negative rate (FNR) of RCNB across the whole cohort was 12.1% (95% CI, 5.3%–18.9%), and exploratory subgroup analysis revealed an excellent ability to predict the presence of residual nodal disease in estrogen receptor-positive breast cancer with a low FNR of 1.6% (95% CI, 0.0%–4.9%) (Table 1). Adopting a strategy where only patients with negative RCNB undergo targeted axillary dissection (TAD) would potentially reduce the FNR of TAD from 9.3% to 2.3%. Furthermore, combination of RCNB and TFNA demonstrated a FNR of 2.2% (95% CI, 0.0%–6.6%), and negative predictive value of 94.1% (95% CI, 81.6%–100.0%) (N = 87) (Table 2). The proposed algorithm based on RCNB and TFNA is helpful in optimizing axillary surgery by avoiding 25 unnecessary attempts as well as 2 false-negative cases in TAD and conferring 10 patients omission of axillary surgery. Conclusions: Combination of RCNB and TFNA allows for an accurate assessment of nodal response after NAC. These results may facilitate reliable identification of suitable candidates for de-escalation or elimination in axillary surgery. Table 1: Overall Cohort Diagnostic Accuracy of Repeated Core Needle Biopsy to Predict Nodal Response (N = 189) Abbreviations: ER, estrogen receptor; HER2, human epidermal factor receptor 2; NPV, negative predictive value; PPV, positive predictive value. Table 2. Diagnostic Accuracy of Repeated Core Needle Biopsy in Breast, Targeted Fine Needle Aspiration and the Combination in Cohort 2 (N = 87) Abbreviations: NPV, negative predictive value; PPV, positive predictive value; RCNB, repeated core needle biopsy; TFNA, targeted fine needle aspiration. Citation Format: Siyu Wu, Jianwei Li, Ying Zhang, Na Hu, Guangyu Liu. PD15-03 Incorporation of Repeated Core Needle Biopsy and Targeted Fine Needle Aspiration to Optimize Axillary Surgery After Neoadjuvant Chemotherapy in Node-positive Breast Cancer: A Prospective Feasibility Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD15-03.