Surgical Considerations for Patients With De Novo Metastatic Breast Cancer Based on Prognostic Group

Advances in systemic therapy for de novo metastatic breast cancer (dnMBC) led to the development of a novel staging system (IVA-D), which stratifies patients into prognostic subgroups based on tumor characteristics and metastatic extent. Overall survival (OS) varies between subgroups; therefore, different treatment approaches may be considered. This study explores the association of surgery of the primary tumor with OS among prognostic subgroups.

Patients with dnMBC (2010-2020) receiving systemic therapy were selected from the National Cancer Database (NCDB) and stratified by prognostic stage group (IVA-D). A landmark analysis was employed with OS defined as the time from diagnosis, plus 12 mo, to death due to any cause. Kaplan-Meier methods, log-rank tests, and adjusted Cox models evaluated OS differences and associations.

Among 42,824 patients, subgroups included IVA 7.3%, IVB 55.7%, IVC 27.4%, and IVD 9.5%. Surgery receipt varied by subgroups: IVA 34.5%, IVB 23.7%, IVC 21.5%, and IVD 29.8% (P < 0.001). After adjustment, surgery was associated with younger age, fewer comorbidities, and private insurance (all P < 0.05). Median OS varied: IVA 84.5 mo, IVB 49.4 mo, IVC 30.8 mo, and IVD 15.3 mo. Among those with IVA disease, surgery patients had better unadjusted 5-y OS (77.5% versus 49.7%, log rank P < 0.001). Despite lower absolute survival in advanced stages (IVB-D), surgery remained associated with significantly higher OS. Adjusted analysis confirmed surgery's association with improved OS (hazard ratio (HR) 0.60, 95% confidence interval (CI) 0.57-0.63).

Surgery of the primary tumor may be associated with better survival for selected patients with dnMBC, and future prospective studies may consider exploring this association using prognostic subgroups.