Is it always necessary to perform an axillary lymph node dissection on patients undergoing neoadjuvant therapy? Outcomes of a retrospective study.

BACKGROUND: Some Trials have demonstrated that the rate of false negative results of a sentinel lymph node biopsy in patients undergoing neoadjuvant chemotherapy is >10%. The aim of this study is to identify the predictive factors of a pathologic complete response in the axilla in order to make a better choice between the performance of an axillary lymphadenectomy or the performance of a sentinel lymph node biopsy. METHODS: All patients diagnosed with positive axillary lymph nodes and achieving a clinical complete response after a neoadjuvant therapy were the object of our study. Radiologic, clinical and histopathological data were collected before and after the neoadjuvant therapy. Data regarding surgery, post-operative period and follow-up were also collected. RESULTS: Clinically negative lymph nodes were reported in 26 patients after they had received a neoadjuvant therapy (59.09%, 26/44). 57.69% of patients, who were clinically cN0 after neoadjuvant therapy, were reported to have a nodal disease on histological examination (pN+). Patients with a pathologic complete response in the axilla are more likely to be Her2-positive (58.33% vs 3.13%, p<0.05) whereas a Luminal B phenotype is more frequently reported in those patients with an incomplete response (62.5% vs 16.67%, p<0.05). CONCLUSIONS: The possibility to detect patients with a lower risk of nodal disease before surgery may reduce the rate of false negative results of sentinel lymph node biopsy in patients receiving a neoadjuvant therapy. KEY WORDS: Axilla, Breast cancer, Lymphnodes, Lymphonodes sentinel.