Considerations for sentinel lymph node biopsy in breast cancer patients with biopsy proven axillary disease prior to neoadjuvant treatment.

Background: Axillary disease can be downstaged with neoadjuvant treatment for breast cancer. We attempted to identify factors to consider in determining whether to perform a sentinel lymph node biopsy in patients with biopsy proven axillary metastases (cN+) prior to neoadjuvant treatment.

Methods: A retrospective chart review was conducted on patients at a single tertiary care center who underwent neoadjuvant treatment followed by surgery between 9/2013 and 2/2017.

Results: 47% of patients with node positive disease prior to neoadjuvant treatment were downstaged to node negative (ypN0) disease. These patients were more likely to have triple negative or Her2 positive disease than those patients who remained node positive (ypN+) as these were more likely to have hormone receptor positive disease. These patients were also more likely to demonstrate complete clinical imaging response of the primary tumor and axilla on preoperative breast MRI.

Conclusions: Tumor biology and clinical response noted on breast MRI can help guide the decision to perform sentinel lymph node biopsy in patients with axillary node positive disease prior to neoadjuvant treatment.