Sentinel lymph node biopsy following neoadjuvant chemotherapy: an evidence-based review and recommendations for current practice.

Sentinel lymph node biopsy (SLNB) at upfront surgery is the gold-standard surgical method for axillary lymph node staging in early stage breast cancer: the technique provides adequate information regarding axillary status, with similar oncological safety and lower morbidity compared to axillary dissection, despite the false negative rates. Neoadjuvant chemotherapy (NACT), traditionally used for locally advanced breast cancer, plays an important role in the treatment of early stage breast cancer, making downstaging possible in axillary lymph node and breast cancer, thus minimizing the impact of surgery and reducing morbidity, as well as enabling patients with residual disease to be selected for adjuvant treatment. In this respect, the role of SLNB has proved controversial, particularly in view of the lack of data from randomized clinical trials on this subject. Currently, the de-escalation of axillary surgery after NACT is mainly based on retrospectives studies and false negative rates. This paper reviews current evidence on the management of axillary surgery following NACT under different circumstances, with suggested recommendations in each scenario: clinically negative nodes at diagnosis and SLNB after NACT, clinically positive nodes at diagnosis and SLNB after NACT, positive SLNB following NACT and finally the possibility of omitting axillary surgery in good responders.