Receipt of Combined Axillary Dissection and Nodal Irradiation Varies by Age

BACKGROUND: Combination axillary lymph node dissection (ALND) and regional nodal irradiation (RNI) poses the greatest risk for breast cancer-related lymphedema. Despite interest in minimizing combination therapy (i.e., ALND+RNI) to avoid complications, concern remains over the oncologic safety of de-escalation in younger populations. This retrospective analysis explores the association between age and receipt of ALND+RNI to gain insight into patterns of axillary management. METHODS: Using the National Cancer Database (2018-2020), age-based differences in ALND+RNI among patients with stage I-III breast cancer undergoing surgery were examined. Patient and treatment characteristics were compared by age (<45, 45-64, and ≥65 years). Multivariable regression assessed associations between age and treatment, adjusting for clinical factors. RESULTS: Among 439,790 patients, 7.5% were aged <45 years, 45.2% were 45-64, and 47.3% were ≥65. Patients aged <45 years (9.9%) were more commonly clinically node-positive (cN+) (vs 5.7% for age 45-64 and 5.5% for age ≥65 years; p<0.001). Younger patients were more likely to undergo ALND (23.8% vs 17.0% vs 16.3%), RNI (23.1% vs 16.9% vs 12.9%), and ALND+RNI (10.6% vs 6.2% vs 4.6%) (all p<0.001). On multivariable analysis, age <45 years had the highest odds of ALND+RNI (odds ratio 1.11; 95% confidence interval 1.03-1.20 vs ≥65 years) overall, but age did not impact ALND+RNI among those receiving neoadjuvant chemotherapy (p=0.209). On sensitivity analyses, those with cN+ molecular subtypes were more likely to receive ALND+RNI than those with clinical N0 disease. CONCLUSION: Women aged <45 years are more likely to receive ALND+RNI. These data highlight an opportunity for further studies targeting management in younger cohorts to limit overtreatment.