Résumé
Abstract only 11055 Background: The optimal management of malignant phyllod tumors (MPT) is poorly documented. Objective:To study the characteristics and outcome of MPT patients (pts). Methods: Retrospective study from the nation-wide French sarcoma network (NetSarc) from 2000 to 2016. Inclusion criteria was central pathological review of MPT. End-points were local recurrence-free survival (LRFS), metastasis-free survival (MFS), and overall survival (OS). Results: 212 pts, from 13 centers, were included. Median age was 52.8 years (range: 16.8 - 90.5). All localized MPT pts (96.7%) underwent surgery with 41.4% of mastectomy. The median size was 5.8 cm (range: 1.5 - 30). R1/R2 resection was achieved in 40.1% pts (26.9% 1-2 mm margin, 12.2% 3-7 mm, 20.3% ≥8 mm), with 44.8% of second surgery (SS) for a final mastectomy rate of 72.6%. Presurgical biopsy was performed in 86.3% and associated with R0 resection ( p=0.044) and better LRFS ( p=0.012). Median follow-up was 4.1 years (range 0-14.8) and revealed 34 (16.6%), 48 (22.9%), 44 (20.8%) events for LRFS, MFS and OS, respectively. The 2-year OS rate was 89%. Prognostic factors found in multivariate analysis are presented in Table 1. Wider margins (≥8mm) were not associated with better outcomes. Adjuvant radiotherapy and chemotherapy were performed in 43.6% and 13.3% respectively and associated with longer LRFS, not significant in multivariate analysis. Conclusions: Mastectomy is associated with better local control, but not with MFS and OS. Age, tumor necrosis and metastatic disease are associated with poor prognosis in MPT pts. Our study suggests that margins of 3 mm are necessary and sufficient for the surgical management of MPT and emphasizes the importance of SS to obtain clear margins. [Table: see text]