Impact of axillary surgery on outcome of clinically node positive breast cancer treated with neoadjuvant chemotherapy

Purpose: Axillary Lymph Node Dissection (ALND) is recommended for breast cancer patients who present with clinically node positive disease (cN1) especially if they have residual nodal disease (ypN+) following neoadjuvant therapy (NAT). It is unknown whether axillary dissection improves outcome for these patients. Methods: A prospectively maintained database was used to identify all patients who were diagnosed with cTis-T4N1M0 breast cancer treated with NAT. Results: In our study, of 292 cN1 breast cancer patients who received NAT, we compared ALND with targeted axillary surgery (TAS) in ypN+ patients. ALND was performed in 75% of the ypN+ subgroup, while 25% underwent TAS. Axillary recurrence occurred in four ALND patients, but no recurrence was observed in the TAS group (p = 0.21). Five-year axillary recurrence-free survival was 100% for TAS and 90% for ALND (p = 0.21). Overall survival at five years was 97% for TAS and 85% for ALND (p = 0.39). Disease-free survival rates at five years were 51% for TAS and 61% for ALND (p = 0.9). Clinicopathological variables were similar between the groups, although some differences were noted. ALND patients had smaller clinical tumor size, larger pathological tumor size, more lymph nodes retrieved, larger tumor deposits, higher rates of extranodal extension, and greater prevalence of macrometastatic nodal disease. Tumor subtype and size of lymph node tumor deposit independently predicted survival. Conclusion: Axillary recurrence is infrequent in cN1 patients treated with NAT. Our study found that ALND did not reduce the occurrence of axillary recurrence or enhance overall survival. It is currently uncertain which patients benefit from axillary dissection.