Neoadjuvant Radiotherapy and Surgery for High-Risk Localized Ewing Sarcoma

Patients diagnosed with high-risk localized Ewing sarcoma will routinely receive standard neoadjuvant chemotherapy. For patients with resectable tumors, preoperative neoadjuvant radiotherapy at a dose of 36-45 Gy will be administered, followed by definitive surgery and subsequent adjuvant chemotherapy. This study does not interfere with standard clinical management and focuses on collecting follow-up data to observe the local recurrence-free survival (LRFS), wound complications, and surgical margin status.

Inclusion criteria

• The subject or their legal representative signs the written informed consent prior to enrollment.
• Age <= 55 years old.
• Histologically confirmed Ewing sarcoma, with FET family (including EWSR1 or FUS) gene rearrangement confirmed by FISH or NGS. Clear FET-non ETS fusion cases are excluded.
• Deemed difficult to achieve a satisfactory surgical margin by 2 or more senior musculoskeletal oncologists.
• ECOG Performance Status: 0-1.
• Expected life expectancy >= 3 months.
• Women of childbearing potential must have a negative pregnancy test within 1 week prior to enrollment and agree to use contraception; male subjects must agree to use contraception or have undergone surgical sterilization during the study.

Exclusion criteria

• No opportunity for surgical resection after neoadjuvant chemotherapy.
• Extensive metastasis with no indication for local surgical resection.
• Uncontrolled concurrent medical conditions.
• Prior radiotherapy to the surgical site during front-line treatment.
• History of other malignant tumors within the past 5 years.
• Inability to cooperate with preoperative neoadjuvant radiotherapy (e.g., due to psychiatric factors).
• Any condition that, in the investigator's judgment, might harm the patient or prevent compliance with study requirements.