The accuracy and relevancy of sentinel lymph node biopsy before neoadjuvant systemic therapy in breast cancer

This study investigated the accuracy and reliability of sentinel lymph node biopsy (SNLB) before neoadjuvant systemic therapy (NAST) has begun in breast cancer patients. The study concluded that SLNB before NAST is highly reliable. The authors suggested that patients with a negative SLNB may be able to avoid lymph node removal and radiation.

SNLB is the standard test for axillary lymph node metastases (spread) in early breast cancer. The axillary lymph nodes are those located under the arm. Many patients with a negative SNLB result may not undergo axillary lymph node dissection (ALND), a surgery to remove the underarm lymph nodes. Omitting ALND from treatment avoids post-operative symptoms such as pain and swelling which are associated with the surgery. These symptoms tend to be aggravated by subsequent radiotherapy.

NAST refers to treatment given before surgery. NAST is now being used in earlier stages of the disease. It is not clear whether a negative SLNB before NAST is reliable as a way to determine who can avoid lymph node removal.

This trial examined the reliability of SLNB before NAST in breast cancer.

This study included 224 patients with clinically node-negative breast cancer. All patients underwent SNLB before NAST followed by ALND. The majority of patients underwent chemotherapy-based NAST. 

92% of patients with a negative SNLB result before NAST were still node-negative after NAST. Of patients with a positive SNLB result, 76.8% had negative nodes after NAST.

A false negative result was seen in 7.4% of patients. Patients found to have a false negative result generally showed a weaker clinical response to NAST.

The study concluded that SNLB before NAST is highly reliable. The authors suggested that omitting ALND and regional radiotherapy may be safe in patients with a negative SNLB and a strong clinical response to NAST.

The study had a small sample group, meaning a larger study is needed to confirm the results. Further, some disagreement exists between the results of this study and those of similar studies, suggesting a need for further research.