The role of adjuvant radiotherapy in patients with malignant phyllodes tumor of the breast: a propensity-score matching analysis.

BACKGROUND AND OBJECTIVES Malignant phyllodes tumor of the breast (MPTB) is a kind of rare tumor. Our objective was to investigate the role of adjuvant radiotherapy (RT) in MPTB patients. METHODS MPTB patients were identified in the Surveillance, Epidemiology and End Results (SEER) database. Kaplan-Meier curves and multivariable Cox proportional hazards analyses were conducted to determine the effect of adjuvant RT on MPTB patients. Propensity-score matching (PSM) method was used to balance the clinicopathological characteristics. RESULTS A total of 1353 MPTB patients were included in our study and the median follow-up time was 99 months (range: 0-331 months). 16.7% (226) MPTB patients received adjuvant RT, of which 49.1% (111) received mastectomy and 50.9% (115) underwent breast conservation surgery (BCS). Patients receiving adjuvant RT were more likely to be white, with better differentiation and larger tumors (p   0.05). In subgroup analysis, no subgroup benefited from adjuvant RT. Exploratory analysis showed a survival benefit trend from adjuvant RT in patients with tumor larger than 50 mm and undergoing BCS. CONCLUSIONS Among MPTB patients, adjuvant RT did not improve OS or DSS. In patients with tumor larger than 50 mm and receiving BCS, a survival benefit trend from adjuvant RT existed.