SAN ANTONIO, TX—Sentinel lymph node biopsy (SLNB) alone is the standard of care for axillary management in breast cancer patients with negative nodes, and its use in appropriately selected candidates with positive sentinel lymph nodes (SLNs) and following neoadjuvant chemotherapy is increasing, according to data presented at the 2015 San Antonio Breast Cancer Symposium.1
Surgical management of the axilla in patients with operable breast cancer has changed significantly in the past 30 years. Axillary lymph node dissection (ALND) was established as the standard of care at the end of the 19th century; however, the concept of the sentinel lymph node (SLN) and clinical validation of lymphatic mapping and SLNB in the late 20th century challenged the therapeutic role of ALND.
Randomized clinical trials evaluating SLNB with or without completion ALND in patients with operable breast cancer and negative SLN(s) established the procedure as the standard of care for nodal staging in this setting. However, performance characteristics of SLNB and factors affecting identification and false-negative rates identified in these trials led to refinement of the original SLN concept and launched additional randomized trials evaluating SLNB alone vs. SLNB with completion ALND in patients with operable breast cancer and limited SLN involvement.
No disease-free or overall survival advantage with completion ALND was seen in these trials, validating greater use of SLNB alone in patients with limited SLN involvement. Results of the AMAROS clinical trial, which compared axillary radiotherapy vs. completion ALND in patients with positive SLN(s), demonstrated that oncologic outcomes between the 2 approaches was similar but axillary radiotherapy offered less morbidity. Thus, for patients who meet the inclusion criteria of the ACOSOG Z11 and the IBCSG 23-01 trials, the axilla can be adequately staged with SLNB alone without completion ALND. For patients who meet the inclusion criteria of the AMAROS trial, axillary radiotherapy may be a better option than completion ALND.
After a decade of debate, SLNB after neoadjuvant chemotherapy has become the arguable standard in patients with operable breast cancer. Neoadjuvant chemotherapy in appropriately selected patients with large, operable breast cancer has resulted in axillary nodal downstaging in 20% to 40% of patients with axillary lymph node involvement at presentation. Even higher rates (more than 50%) in patients with HER2+ breast cancer receiving chemotherapy plus anti-HER2 therapy, SLNB has the potential to further reduce the extent of axillary surgery; an approach that now includes patients with clinically or biopsy proven axillary node involvement, become clinically node-negative after neoadjuvant chemotherapy, and have negative SLNB.
Axillary management in patients with operable breast cancer has evolved significantly in the past 30 years. Axillary radiotherapy has emerged as an alternative to ALND in breast cancer patients with positive SLN(s), minimizing treatment sequelae, and clinical trials are currently exploring the potential to further reduce the role of axillary radiotherapy and completion ALND in patients with nodal response to neoadjuvant chemotherapy.
1. Mamounas EP. Optimal management of the axilla: A look at the evidence. Paper presented at: San Antonio Breast Cancer Symposium; December 9-12, 2015; San Antonio, TX.