Effect of Axillary Dissection vs No Axillary Dissection on 10-Year Overall Survival among Women with Invasive Breast Cancer and Sentinel Node Metastasis: The ACOSOG Z0011 (Alliance) Randomized Clinical Trial

Prior to the ACOSOG Z0011 trial (also known as the Z11 trial), the standard of care after identification of positive axillary lymph nodes following sentinel lymph node biopsy (SLNB) was a completion axillary clearance. This was despite the fact that the majority of such women have no further nodal disease, suggesting they have been overtreated. In addition, evidence from earlier trials such as the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-04 ¹ had demonstrated no survival advantage when comparing axillary clearance, axillary radiotherapy or no further axillary treatment. The Z11 trial set out to demonstrate that completion axillary clearance may be safely omitted in women with low-risk cancers, thus reducing morbidity. Despite its flaws, it was perhaps the most highly impactful and practice-changing trial of recent years.