Axillary Lymph Node Treatment Guided by Naocarbon Tracing After Neoadjuvant Chemotherapy

A total of 100 patients who are first diagnosed with breast cancer (stage N2 or N3) at the Liaoning Oncology Hospital will be recruited. Inclusive criteria: 1) Invasive breast cancer confirmed by biopsy and histology; 2) based on prone CT scan and Doppler ultrasound, axillary stage cN2-3; 3) agree and meet the requirements for NAC; 4) meet surgical requirements and agree to undergo surgery after NAC; 5) the regime of NAC follows the NCCN recommendations. Exclusive criteria: previous history of breast cancer or other malignant tumors. Period of investigation: 2 years. After informed consent is obtained, under ultrasound guidance, the metastatic lymph node with the largest diameter (\> 1 cm) is selected and injected under the cortex with 0.3 ml of nanocarbon. If the cortex and medulla are difficult to distinguish, inject on the surface of the node. Patients with efficacy for NAC should complete the scheduled cycles of NAC. Alteration of NAC regime is allowed for patients whose initial NAC is inefficacious, as guided by the physicians. Surgery is performed within four weeks after completion of the last cycle of NAC. Axillary lymph nodes are assessed using CT scan. For patients with neoadjuvant efficacy of CR and PR, axillary surgery is performed under fluorescent tracing. SLNB is performed for patients with extensive black staining nodes. Standard ALND is performed if SLN is positive. For patients with less than three black-stained nodes, pALND will be performed rather than SLNB. If axilary lynph nodes under the ICBN are proved positive by frozen histology, ALND is then performed. For those with neoadjuvant efficacy of SD or PD, pALND will be performed if there are extensive black-stained nodes. Standard ALND will be performed if lymph nodes are positive as assessed by intraoperative frozen histology. ALND will be performed if the number of black-stained nodes is less than 3. All the clinical information and imaging data will be securely preserved, including surgical procedure, black-stained and metastasized lymph nodes. Short-term observatory measures include axillary drainage (quantity, extubation time) and upper limb lymphatic drainage (changes in arm circumference 10cm above and below the elbow pre and post surgery. Long-term observatory measures include axillary recurrence rate and lymphoedema 3-5 years after surgery.