De-escalation of axillary interventions in the management of breast cancer patients following neoadjuvant systemic treatment.

The role of axillary surgery in the management of breast cancer continues to evolve as our understanding of breast cancer biology improves, coupled with an increasing availability and efficacy of systemic therapy options. In the current context, the main goal of axillary surgery is staging. In this review, we discuss the role of axillary surgery in patients receiving neoadjuvant systemic therapy and appraise the current state of de-escalation of axillary interventions. We argue that accuracy of limited axillary staging procedure is important, not so much from axillary control point of view but from the systemic undertreatment point of view. We suggest that comparative evaluation of different limited axillary staging procedures from oncological safety perspective should therefore not be based on local axillary control endpoint. We discuss the comparative diagnostic accuracy of sentinel lymph node biopsy (SLNB) vs. targeted axillary dissection (TAD). SLNB does not meet the level of accuracy needed for safe de-escalation in node-positive patients, particularly true de-escalation of axillary intervention, where the omission of completion axillary lymph node dissection (ALND) is not replaced with axillary radiotherapy. We discuss the arguments against the use of intraoperative assessment of lymph nodes in this context. We identify the areas of unmet research need, these include developing tools to predict residual axillary nodal burden in patients with incomplete nodal response, and true de-escalation studies in this patient population, especially those who will receive extended or modified adjuvant treatment. We also underscore the urgent need for research in patients with locally advanced breast cancer (LABC) with an emphasis on tumour biology paradigm.