Management of the axilla in breast cancer: outcome analysis in a series of ductal versus lobular invasive cancers.

Axillary lymph node dissection (ALND) has been considered essential for the staging of breast cancer (BC). As the impact of tumor biology on clinical outcomes is recognized, a surgical de-escalation approach is being implemented. We performed a retrospective study focused on surgical management of the axilla in invasive lobular carcinoma (ILC) versus invasive ductal carcinoma (IDC). 1151 newly diagnosed BCs, IDCs (79.6%) or ILCs (20.4%), were selected among patients treated at our Breast Cancer Unit from 2012 to 2018. Tumor characteristics and clinical information were collected and predictors of further metastasis after positive sentinel lymph node biopsy (SLNB) analyzed in relation to disease-free survival (DFS) and overall survival (OS). 27.5% of patients with ILC had ≥ 3 metastatic lymph nodes at ALND after positive SLNB versus 11.48% of IDCs (p = 0.04). Risk predictors of further metastasis at ALND were the presence of > 2 positive lymph nodes at SLNB (OR = 4.72, 95% CI 1.15-19.5 p = 0.03), T3-T4 tumors (OR = 4.93, 95% CI 1.10-22.2, p = 0.03) and Non-Luminal BC (OR = 2.74, 95% CI 1.16-6.50, p = 0.02). The lobular histotype was not associated with the risk of further metastasis at ALND (OR = 1.62, 95% CI 0.77-3.41, p = 0.20). ILC histology is not associated with higher risk of further metastasis at ALND in our analysis. However, surgical management decisions should be taken considering tumor histotype, biology and expected sensitivity to adjuvant therapies.