Trade-offs associated with axillary lymph node dissection with breast irradiation versus breast irradiation alone in patients with a positive sentinel node in relation to the risk of non-sentinel node involvement: implications of ACOSOG Z0011

Abstract

Recent data suggest that axillary lymph node dissection (ALND) may be unnecessary for patients with positive sentinel lymph node biopsy (SLNB) receiving whole-breast irradiation (ACOSOG Z0011). The purpose of this study was to use decision analysis with simulated patients to determine subgroups with positive SLNB who may still benefit from ALND. We performed a decision analysis simulating axillary recurrence (ALR) risk, lymphedema, and quality of life following breast-conserving surgery (BCS) with positive SLNB and either completion ALND and whole-breast radiation (ALND + BRT) or breast radiation (BRT) alone. Simulated patients were divided into two risk groups based on the likelihood of disease in non-sentinel axillary nodes after positive SLNB: those with risk 30-60 % ("high-risk") and those with risk under 30 % ("low-risk," similar to average Z0011 patients). In simulated patients aged 55, BRT alone resulted in 1 month of additional QALE in the low-risk group versus ALND + BRT, while ALND + BRT resulted in 9.7 months of additional QALE in the high-risk group versus BRT alone. Overall survival was similar at 5 years in this simulation with either treatment in both groups, but ALND + BRT was superior to BRT alone at 20 years in the high-risk group (42 vs. 38 %). In the low-risk group, BRT alone is preferable unless ALR risk with BRT is greater than 1.6 % or lymphedema risk with ALND is under 10 %. Patients eligible for Z0011 but at a higher risk of residual nodal disease following BCS and positive SLNB may benefit from ALND + BRT, rather than BRT alone.