Abstract
BACKGROUND: Breast phyllodes tumors (PT) are rare fibroepithelial tumors classified by the World Health Organization into benign, borderline, and malignant subtypes. Although surgery is the primary treatment, local recurrence remains a concern. The role of postoperative radiotherapy (PORT) in improving local control remains unclear. OBJECTIVES: This study aimed to investigate the effect of PORT in patients with borderline PT (BoPT) and malignant PT (MPT) after R0 resection (complete resection without tumor margins) and to identify prognostic factors related to local recurrence-free survival (LRFS) and overall survival (OS). DESIGN: This was a retrospective multicenter study. METHODS: We retrospectively evaluated patients with BoPT and MPT who underwent R0 resection between January 2002 and October 2023. Propensity score matching was used to balance the covariates between the PORT (n = 37) and non-PORT (n = 83) groups. Kaplan-Meier curves were used to estimate the 5-year LRFS and OS, while Cox regression analyses were used to identify prognostic factors. Subgroup analysis was used to assess the potential benefits of radiotherapy. RESULTS: Of 480 patients, 438 (91.25%) underwent surgery alone and 42 (8.75%) received PORT. PORT did not improve the LRFS or OS. After matching, 5-year LRFS (71.42% vs 70.17%, p = 0.58) and OS (82.41% vs 80.02%, p = 0.82) were similar between the groups. Multivariate analysis of matched samples showed that axillary lymph node metastasis was significantly associated with LRFS and OS. Malignant heterologous elements were independent poor prognostic factors for LRFS. No subgroup benefited from radiotherapy. CONCLUSION: In our study, PORT did not significantly improve LRFS or OS in patients with BoPT and MPT. Key prognostic factors may guide treatment decisions in these patients.