ASO Author Reflections: Completion Axillary Dissection Can Be Avoided but Inconsistent Trial Design Complicates Choosing Between Alternative Strategies

Excerpt

The highly publicized randomized controlled trial (RCT) American College of Surgeons Oncology Group (ACOSOG) Z00111 seemingly established the oncologic safety of omitting completion axillary lymph node dissection (cALND) for sentinel-node-positive women who were cN0. However, debate around this trial’s early termination and radiation field protocol violations2 eclipsed a more comprehensive assessment of the remaining randomized literature. In addition to comparing observation and cALND, as in the case of ACOSOG Z0011, trials have investigated axillary radiotherapy (ART) as an alternative to cALND. Most of these studies are noninferiority trials, which recognize the secondary benefits of observation or ART compared with cALND (e.g., lymphedema risk) and only seek to demonstrate that the alternative strategy is not worse than the standard of care with respect to the primary outcome by some prespecified amount (noninferiority margin).3 Our aim was to systematically review all RCTs comparing observation or ART with cALND in sentinel-node-positive women with a particular focus on assessing bias specific to noninferiority trials. …