Is it always necessary to perform an axillary lymph node dissection after neoadjuvant chemotherapy for breast cancer?

Recent prospective studies support the feasibility of performing sentinel lymph node biopsy following neoadjuvant chemotherapy in initially fine-needle aspiration cytology or ultrasound-guided biopsy-proven node-positive breast cancer. The main aid is to identify preoperative features that help us predict a complete axillary response to neoadjuvant chemotherapy in these patients and thus select the candidates for sentinel lymph node biopsy post-neoadjuvant chemotherapy to avoid unnecessary axillary lymphadenectomy.

A retrospective observational study with a total of 150 patients, biopsy-proven node-positive breast cancer who underwent neoadjuvant chemotherapy followed by breast surgery and axillary lymphadenectomy were included and retrospectively analysed. A predictive model was generated by a multivariate logistic regression analysis for pathological complete response-dependent variable.

The response of the primary lesion to neoadjuvant chemotherapy according to post-treatment magnetic resonance imaging, Her2/neu overexpression and a low estrogen receptor expression are associated with a higher rate of nodal pathologically complete response. The multivariant model generated a receiver operating characteristic curve with an area under the curve of 0.79 and a confidence interval of 0.72-0.87 at a 95% level of significance.

This model could be a helpful tool for the surgeon to help in predicting which cases have a higher likelihood of achieving a pathologically complete response and therefore selecting those who may benefit from a post-neoadjuvant chemotherapy sentinel lymph node biopsy and avoid unnecessary axillary lymphadenectomy.