Retrospective, Observational, Multicentric Study Aimed at Developing a Model for Prediction of Axillary Lymph Node Status After Neoadjuvant Chemotherapy in Breast Cancer Patients

The management of patients diagnosed with breast cancer (BC) with axillary nodal involvement is still a controversial topic. These patients' treatment usually involves the administration of a neoadjuvant chemotherapy (NAC) in order to improve survival rates and increase local disease control. Depending on the tumor subtype, an axillary pathologic complete response (pCR) is achieved in 40-70% of initially axillary node-positive patients (cN+). Concerning patients with an axillary pCR, thus a clinically negative node status (cN0), axillary lymphadenectomy (ALND) might be replaced by less invasive surgical approaches and sentinel lymph node biopsy (SLNB) is considered, in these cases, an effective alternative treatment.

However, the relatively high false negative rates, reported in several validation trials, points out the complexity concerning these patients' treatment. Moreover, histological findings' predictive and prognostic value, after SLNB, of micrometastases and isolated tumor cells (ITCs) is still unclear.

Currently, dual-tracer-guided lymph node biopsy and the surgical removal of ≥ 3 sentinel lymph nodes are known as effective strategies aimed to reduce the false negative rates.

There are several ongoing clinical trials to understand and define the best approach for these patients.

Nowadays, there's great interest in potential prognostic role of systemic inflammation's biochemical markers such as neutrophil-to-lymphocyte ratio (NLR). Systemic inflammation's markers may be nodal pCR's predictors after NAC in node-positive breast cancer patients.

The aim of the study is to develop and validate a pre-operative model, able to predict pCR after NAC to select the patients suitable for a surgery de-escalation strategy.