Abstract:

In the era of effective systemic therapy and precise radiotherapy, neoadjuvant treatment (NAT) for breast cancer can de-escalate breast cancer treatment to conserve breast and spare axillary lymph node dissection (ALND). At present, high axillary nodal pathologic complete response (apCR) is achieved in patients with human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancer (TNBC), and it is hopeful to realize the axillary de-escalation management. It is recommended that sentinel lymph node (SLN) biopsy (SLNB) is a feasible alternative to ALND in primary clinical lymph node negative (cN₀) patients, and the presence of lower residual tumor burden in SLN after NAT may be considered as a replacement for ALND with radiotherapy. The feasibility of the patients with initial clinical lymph node positive (cN⁺) turning to conventional SLNB after NAT is still being questioned. The main obstacle is the high false negative rate of SLNB after NAT, residual tumor cells in the axilla cannot be accurately predicted, and the risk of postoperative axillary recurrence and metastasis cannot be determined. The false negative rate of SLNB may meet the clinical requirement under the condition of combined tracing, more than 3 SLNs detected, and lower clinical axillary metastatic tumor burden. However, the quality of SLNB after NAT cannot be effectively improved due to tumor cells blocking lymphatic vessels and affecting the drainage of blue dye or radionuclide. Therefore, optimization of SLNB technology needs to be implemented after NAT. Targeted axillary lymph node dissection (TAD) is a precise surgical procedure for the detection of metastatic axillary lymph nodes, and clips were placed on the metastatic lymph nodes before NAT and targeted to detect the lymph nodes after NAT. It can further reduce the false negative rate of SLNB after NAT and improve the accurate assessment of residual tumor burden in axillary lymph nodes after NAT. TAD is expected to be a safe and reliable axillary staging technique for breast cancer patients after NAT. This article reviewed the de-escalation treatment of NAT in initial cN+ patients and the research progress of TAD.

Key words: Breast cancer, Sentinel lymph node biopsy, Targeted axillary lymph node dissection, Neoadjuvant treatment