Purpose: Although axillary lymph node status has traditionally been a key factor in informing adjuvant breast cancer therapy recommendations, this information may be less relevant as our focus shifts more towards tumor biology, particularly in older patients where comorbidity influences treatment decisions and nodal staging and/or surgery may not improve outcomes. We examined patterns of axillary surgery and associations between axillary surgery and receipt of adjuvant treatment in older breast cancer patients.
Methods: Women aged ≥ 65 years with clinically node-negative, stage I-II breast cancer treated between 2012 and 2013 were identified using the National Cancer Data Base. Using multivariable logistic regression, we examined associations between axillary surgery and age, adjusting for patient, clinical, and facility factors. We also examined receipt of adjuvant treatment by nodal surgery.
Results: Among 68,205 women, 40.1% were aged 65-70, 24.5% were 71-75, 17.4% were 76-80, and 18.0% were > 80. Overall, 91.2% had axillary surgery (67.8% sentinel lymph node biopsy, 11.7% axillary lymph node dissection, 11.7% unspecified/unknown axillary surgery); 88.0% of those aged ≥ 70 with lower risk, hormone receptor-positive tumors underwent axillary surgery. In adjusted analyses, compared to patients aged 65-70, increasing age was associated with lower odds of any axillary surgery (ages 71-75: OR 0.64, 95% CI 0.57-0.71; ages 76-80: OR 0.33, 95% CI 0.30-0.37; age > 80: OR 0.08, 95% CI 0.07-0.08). Axillary surgery was associated with higher odds of receipt of radiation after breast conservation and receipt of chemotherapy in human epidermal growth factor 2-positive disease.
Conclusions: In a large nationwide dataset, the vast majority of older women with clinically node-negative breast cancer underwent axillary staging despite uncertainty about its impact on survival, particularly for those with lower-risk disease. Further study on how to tailor node assessment in older patients is warranted.
Keywords: Adjuvant therapy; Axillary surgery; Breast cancer; Elderly; Lymph nodes.