Radiotherapy or Surgery of the Axilla after a Positive Sentinel Node in Breast Cancer (EORTC 10981-22023 AMAROS): A Randomised, Multicentre, Open-Label, Phase 3 Non-Inferiority Trial

It has long been known that axillary surgery does not confer a survival advantage, following the seminal National Surgical Adjuvant Breast and Bowel Project (NSABP) B-04 ¹ (and other) trials, albeit at the expense of reduced rates of regional control. Sentinel node biopsy became the standard of care for staging women with clinically uninvolved axillae, but this was usually followed by completion axillary clearance in women with axillary metastases. The NSABP B-04 had also shown that axillary radiotherapy gave equivalent rates of survival as surgical clearance; however, it had not investigated quality of life or rates of lymphoedema. The AMAROS (After Mapping of the Axilla: Radiotherapy or Surgery?) trial set out to assess locoregional control and adverse events related to completion axillary clearance versus axillary radiotherapy in women with positive sentinel nodes.