Analysis of the Current Status of De Novo Stage IV Breast Cancer Surgery in China and the United States: A multicenter real-world study

Background De novo stage IV breast cancer, characterized by distant metastases at diagnosis, poses significant treatment challenges. While systemic therapy remains the cornerstone of treatment, the role of surgical intervention for the primary tumor remains controversial. This study aimed to compare surgical treatment patterns and survival outcomes in de novo stage IV breast cancer patients between China and the United States using two large-scale national databases, to inform personalized treatment strategies and future guideline development. Methods This multicenter, retrospective cohort study included de novo stage IV breast cancer patients who underwent surgery from the National Cancer Center Oncology Information Database (NCCOID) and the Surveillance, Epidemiology, and End Results (SEER) database. The two cohorts were compared in clinical characteristics, treatment strategies, and survival outcomes. Kaplan-Meier analysis and multivariate Cox regression were used to identify factors associated with overall survival (OS). Results A total of 2,037 patients from China (2013–2020) and 3,175 from the US were included. Compared to SEER, the NCCOID cohort had a higher proportion of younger patients and more cases of T2-stage tumors. Mastectomy was the predominant surgical method in both countries, though breast-conserving surgery (BCS) was more common in the US. Chinese patients were more likely to receive preoperative systemic therapy. The NCCOID cohort showed superior OS (1-year: 91.5%, 3-year: 77.4%, 5-year: 67.9%) compared to SEER (1-year: 87.7%, 3-year: 62.8%, 5-year: 46.4%). Subgroup analyses revealed better survival in patients with HR + status, T-staging for smaller tumors, and bone-only metastases. Multivariate Cox regression confirmed that younger age (35–54), HR + status, HER2 + status, and limited metastases (especially bone-only metastases) were independently associated with improved OS. Conclusion Surgical treatment for de novo stage IV breast cancer is approached differently in China and the US, with variations in patient age, tumor characteristics, and systemic therapy timing. Selected patients—particularly those with HR + tumors, HER2 + tumors, smaller primary lesions, and limited metastases—may benefit from surgical resection. These findings support a personalized approach to surgery, emphasizing multidisciplinary decision-making. Prospective studies are needed to validate optimal surgical timing and patient selection.