Association Between Axillary Surgical Management and Survival for Patients With De Novo Metastatic Breast Cancer

The optimal management of the axilla in patients with de novo metastatic breast cancer (MBC) undergoing breast surgery remains unclear. This study aimed to evaluate the association between axillary surgical management and survival outcomes for patients with de novo MBC.

This retrospective single-center cohort study included patients with de novo extra-nodal MBC treated at Institut Curie between 2008 and 2019 and registered in the ESME database. Patients were categorized according to axillary management: axillary lymph node dissection (ALND) versus sentinel lymph node biopsy (SLNB) or no axillary surgery. Progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier methods. Inverse probability of treatment-weighting (IPTW) based on a propensity score was used to reduce selection bias.

The study included 246 patients including 182 (74%) who underwent ALND, 54 (21%) who received SLNB, and 10 (4%) who had no axillary surgery. After a median follow-up period of 60.3 months (95% confidence interval [CI], 55.9-64 months), axillary surgical management was not associated with survival outcomes. In IPTW-weighted analyses, ALND was not associated with better PFS than SLNB or no axillary surgery (hazard ratio [HR], 0.82; 95% CI, 0.53-1.25; p = 0.4), nor with improved OS (HR, 1.19; 95% CI, 0.64-2.25; p = 0.6). Patterns of disease progression were similar between the groups, with no increased nodal progression observed in the SLNB group.

For patients with de novo MBC undergoing breast surgery, ALND was not associated with improved survival. These findings support a more conservative axillary approach for this population given the limited therapeutic benefit and potential morbidity of extensive axillary surgery.