OBJECTIVE:~To determine the accuracy of on-treatment core needle biopsy in breast to predict nodal response after neoadjuvant chemotherapy.~OUTLINE:~Early breast cancer patients aged above 18 and below 70 years with biopsy-confirmed, clinically T1-4, N1-3, and M0 disease are eligible for this study. Breast cancer is proven pathologically in all patients using the baseline core needle biopsy, and the skin of all patients is tattooed at the baseline. Metastatic lymph nodes are diagnosed with core needle biopsy or fine needle aspiration. All the patients undergo clip placement into node with biopsy-confirmed metastases at the time of diagnosis. For patients who were not evaluated as progressive disease by the latest imaging measurement, repeated CNB (RCNB) was performed after 2-4 cycles of NAC, depending on the total cycles of NAC., repeated core needle biopsy is conducted within the baseline tattooed area after 2 to 4 cycles of neoadjuvant chemotherapy, depending on the total cycles of chemotherapy. Tissue is acquired from different sections of the lesion from different angles to minimize the impact of tumor heterogeneity. For each patient, 3 to 4 tissue specimens are collected and sent for pathological review to examine whether there is residual malignancy (residual cancer, pleomorphic tissue) in the tumor site that is tattooed.~All the patients receive planned axillary surgery after completion of neoadjuvant chemotherapy. the surgical approach was determined by the treating breast surgical oncologist including targeted axillary dissection (TAD) or axillary lymph node dissection, mainly based on the intraoperative TAD results~PROJECTED ACCRUAL: A total of 180 patients will be accrued for this study within 5 years.
Preoperative identification of patients with pathologic complete response or residual disease in axilla can aid in tailoring subsequent axillary surgery including omission of axillary surgery based on tumor biology and response to neoadjuvant chemotherapy.