Analysis of the Current Status of De Novo Metastatic Breast Cancer Surgery in China and the USA: A Multicenter Real-World Study.

Background: De novo metastatic breast cancer-defined by distant metastases at diagnosis-poses treatment challenges. While systemic therapy is standard, the benefit of primary tumor surgery remains debated. This study compared surgical patterns and survival in China versus the USA to provide evidence for personalized strategies.

Patients and methods: In this multicenter retrospective cohort study, patients with surgically treated de novo metastatic breast cancer were identified from the National Cancer Center Oncology Information Database (NCCOID; n = 2037, 2013-2020) and Surveillance, Epidemiology, and End Results (SEER) (n = 3175, 2013-2020). Clinical features, treatments, and overall survival (OS) were contrasted. Kaplan-Meier curves and multivariable Cox models identified OS predictors.

Results: Compared with SEER, NCCOID patients were younger and had more T2 tumors; mastectomy predominated in both, though breast-conserving surgery was more frequent in SEER, and preoperative systemic therapy was more common in NCCOID. NCCOID achieved superior OS (1 year, 3 year, 5 year: 91.5%, 77.4%, 67.9%, respectively) versus SEER (87.7%, 62.8%, 46.4%). Improved survival was seen in hormone-receptor-positive tumors, smaller primary lesions (lower T category), and bone-only metastases. Multivariate analysis confirmed age 35-54 years, HR+ and HER2+ status, and limited (especially bone-only) metastases as independent favorable factors.

Conclusions: Surgical management of de novo metastatic breast cancer differs between China and the USA. Select patients-particularly those with HR+ or HER2+ tumors, small primaries, and limited metastases-may benefit from resection, underscoring the need for multidisciplinary, personalized decision-making and prospective validation of optimal surgical timing.