Effects of adjuvant radiotherapy on borderline and malignant phyllodes tumors: A systematic review and meta-analysis

The standard treatment for borderline and malignant phyllodes tumors is wide local excision (margins ≥1 cm), in the context of either breast-conserving surgery (BCS) or total mastectomy (TM). Due to the high risk of local recurrence (LR) following surgical intervention alone, the addition of adjuvant radiotherapy (RT) has been previously investigated; however, the conclusions have been inconsistent. This systematic review and meta-analysis was designed to assess the efficacy of adjuvant RT for borderline and malignant phyllodes tumors. Pubmed and Web of Science were systematically searched to identify relevant studies assessing the effect of adjuvant RT on borderline and malignant phyllodes tumors from the inception of this technique through May, 2014. A total of 8 studies were identified among 332 citations. In this meta-analysis, patients who received adjuvant RT had a lower relative risk of LR [hazard ratio (HR) = 0.43, 95% confidence interval (CI): 0.23-0.64]. The absolute risk difference was 10.1% (95% CI: 4.9-17.6), corresponding to a number needed to treat of 10. Our pooled meta-analysis clearly demonstrated a decreased risk of LR in patients with borderline and malignant phyllodes tumors who received RT following BCS (HR=0.31, 95% CI: -0.10-0.72). However, the combined HR for LR in the TM group did not demonstrate that adjuvant RT was superior to no RT (HR=0.68, 95% CI: -0.28-1.64). No significant differences were observed in overall survival (OS) or disease-free survival (DFS) between the two groups. Our analysis suggested that adjuvant RT for borderline and malignant phyllodes tumors decreased the LR rate in patients undergoing BCS. However, adjuvant RT was not found to exert an effect on OS or DFS.