Axillary lymph node removal in metastatic breast cancer.

Background: Several prospective studies have found that local surgical resection did not improve the survival of patients with metastatic breast cancer (dnMBC). However, a significant portion of dnMBC patients still undergo local surgery, and the role of axillary lymph node dissection (ALND) in dnMBC patients remains unclear. This study aimed to investigate the effect of ALND in patients with dnMBC.

Methods: We included patients diagnosed with dnMBC between 2010 and 2020 using the data from the Surveillance, Epidemiology, and End Results program. The Chi-square test, binomial logistic regression, propensity score matching (PSM), Kaplan-Meier method, and multivariate Cox proportional models were employed for statistical analysis.

Results: A total of 6,838 patients were identified, with 5,562 (81.3%) in the ALND group and 1,276 (18.7%) in the non-ALND group. Being diagnosed in later years emerged as an independent predictive factor related to the receipt of ALND (P=0.003). Before PSM, the 5-year breast cancer-specific survival (BCSS) was 51.1% and 38.2% in those with and without ALND, respectively (P<0.001). The 5-year overall survival (OS) was 45.9% and 32.3% in those with and without ALND, respectively (P<0.001). ALND was identified as an independent prognostic factor related to better BCSS (P<0.001) and OS (P<0.001) compared to the non-ALND group. Similar findings were observed after PSM. The outcomes were significantly better in the ALND group than in the non-ALND group in most subgroups. However, the number of removed lymph nodes did not show a significant association with BCSS (P=0.27) and OS (P=0.29).

Conclusions: Our study suggests that ALND is associated with improved survival outcomes in dnMBC patients. These findings advocate for a re-evaluation of the role of surgical interventions in dnMBC, emphasizing the need for personalized treatment strategies that consider the potential benefits of ALND.