Regional nodal irradiation in the setting of sentinel node biopsy

The need for axillary lymph node dissection (ALND) in patients with invasive breast cancer (IBC) has been a topic of great debate in the last decade. The role of axillary management in patients with sentinel lymph node biopsy (SLNB) negative or micrometastatic disease is well established after multiple trials demonstrated no survival benefit with the addition of ALND (NSABP B32, IBCSG 23-01, AATRM048); yet, there remains controversy in the management of SLNB positive disease. ALND has traditionally been the standard of care following positive SLNB, however, results from recent studies have identified that further surgical exploration of the axilla may be overtreatment in these patients. In order to de-escalate treatment, non -surgical options such as regional nodal irradiation (RNI) and neoadjuvant chemotherapy (NAC) have been increasingly explored. Trials evaluating the role of RNI following positive SLNB have suggested that RNI is non -inferior to ALND and provides superior outcomes with an improved toxicity profile (AMAROS, MA.20, EORTC 22922). NAC has been explored in the treatment paradigm in patients with locally advanced disease, however, the role of SLNB and RNI in this setting remains unequivocal. This review aims to provide an update on the role of RNI following SLNB in IBC using an evidence -based approach.