Options to Determine Pathological Response of Axillary Lymph Node Metastasis after Neoadjuvant Chemotherapy in Advanced Breast Cancer.

Increasing use of neoadjuvant therapy in large tumors or node positive disease in breast cancer patients or hormone negative and HER 2 overexpressing cancers often gives rise to complete clinical response, with resolution of disease in the breast and axilla. These results have raised important questions to deescalate loco-regional surgical treatment options with minimum recurrence risk and treatment related morbidity. Although there is excellent prognosis following clinical response, the primary goal of surgery still remains to confirm complete pathological response in the biopsied node that was previously positive and now clinically/radiologically negative (ycN0). Biopsied lymph nodes are often marked with a clip to allow future identification at the time of definitive surgery. The goal of lymph node surgery in oncology is that it should be accurate, hence the significance of localizing the biopsied node. This article aims to review the different options to localize the deemed positive node at the time of definitive surgery, in order to help determine pathological response after neoadjuvant therapy.