Primary breast sarcoma (PBS) is a rare and heterogeneous group of malignancies with limited publications. We obtained data from the Surveillance, Epidemiology, and End Results Program and performed analysis to determine clinicopathological characteristics of PBS and estimate their associations with overall survival (OS) and cancer-specific survival (CSS). Median age of PBS was 55-59 years and median OS was 108 months. Age, overlap or entire breast involvement, tumor histology, and tumor spread were associated with poor survival outcomes. In the multivariable analysis, tumor size, lymph node involvement, distant metastasis and histologic grade were correlated with survival outcomes (P < 0.001). In M0 patients, mastectomy was associated with worse survival outcomes compared with breast conservative surgery (BCS) (adjusted hazard ratio [adjHR], 1.80; 95% CI, 1.31-2.47), regardless of tumor size, tumor grade, tumor histology or radiation history. Adjuvant radiation improved survival outcomes in patients with tumor size >5 cm (adjHR, 0.63; 95% CI, 0.43-0.91), but not in patients with tumor size ≤ 5 cm. Our study demonstrated clinicopathological characteristics of PBS in the US population and supports performing BCS if R0 resection can be achieved, with radiation if tumor size is over 5 cm.
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