Trends in the rate of axillary clearance following the publication of the ACOSOG Z0011 trial: A systematic review.

Axillary surgery for breast cancer has seen significant de-escalation in the past three decades. The ACOSOG Z0011 trial suggested that completion axillary clearance was not necessary in women with low disease burden after sentinel node biopsy (SLNB). Flaws in the design of the trial undermined confidence in its findings which delayed widespread adoption and caused practice heterogeneity globally. This systematic review evaluated the impact of Z0011 (and similar trials) on the rate and extent of axillary conservation in women with node-positive, low-risk early breast cancer. A search was conducted on the Ovid MEDLINE, Scopus, Web of Science and COCHRANE databases. Screening of titles and abstracts was undertaken according to eligibility criteria. Data were quality assessed using the ROBINS-1 and Robvis tools. The review retrieved 1362 papers, of which 30 papers were included, representing data from 290,754 women across nine countries. All articles were retrospective cohort studies. Included studies showed a statistically significant downward temporal trend in rates of ALND following the publication of the Z0011 trial but the extent of change ranged from a 5.6 %-73.4 % reduction in axillary clearance rates. This review demonstrated the Z0011 trial has been practice-changing. However, it also identified that few patients are eligible for de-escalation due to tight inclusion criteria. Finally, most articles were from Western countries, from research-focused hospitals, which limits generalizability. Further research across a wider range of settings is needed to understand the extent to which Z0011 has been implemented globally.