Ewing’s Sarcoma of the Head and Neck: Margins are not just for surgeons

Background, Methods: To describe the characteristics, treatments (systemic/local), and outcome (oncological/functional) of French patients with head and neck Ewing's sarcomas (HNES) registered in the Euro-Ewing 99 (EE99) database. Specific patient-level data were reviewed retrospective. Results: Forty-seven HNES patients in the EE99 database had a median age of 11 years, 89% had bone tumors (skull 55%, mandible 21%, maxilla 11%), 89% had small tumors (<200 mL), and they were rarely metastatic (9%). Local treatment was surgery radiotherapy (55%), exclusively surgery (28%), or radiotherapy (17%). Metastatic relapses occurred in five patients with high relapse risk factors (metastasis at diagnosis, poor histological response, large tumors). Local progression/relapses (LR) after exclusive radiotherapy occurred in three patients with persistent extra-osseous residue and in four patients considered R0 margins (postchemotherapy surgery, without postoperative radiotherapy [PORT]), reclassified by pathological review as R1a. Pathological review reclassified 72% of R0 margins: 11/18 to R1a and 2/18 to R2. Five patients had confirmed R0 margins after postchemotherapy surgery without PORT and had no LR Eight patients had R2 margins (initial surgery without previous chemotherapy, with PORT) and had no LR With a median follow-up of 9.3 years, the 3-year LR rate, EFS, and OS were 84.8%, 78.6%, and 89.3%, respectively. Among the 5-year survivors, 88% had long-term sequelae. Conclusion: To optimize HNES management, patients should be treated from diagnosis in expert centers with multidisciplinary committees to discuss treatment strategy (type of surgery, need for PORT) and validate surgical margins.