Modern Therapy for Spinal and Paraspinal Ewing Sarcoma: An Update of the University of Florida Experience.

PURPOSE: In 2010, we published a comprehensive review of our institutional outcomes about treating children with spinal and paraspinal Ewing sarcoma using photon therapy. Multimodality therapy was associated with fair disease control but also with serious toxicity, including a 37% rate of grade 3 or greater toxicity. We therefore sought to assess our more recent experience about treating children with more modern technology and treatment regimens. METHODS AND MATERIALS: Between 2010 and 2021, 32 pediatric patients with nonmetastatic spinal and paraspinal Ewing sarcoma were treated at University of Florida and enrolled in a retrospective outcome study. Median age at diagnosis was 9.8 years (range, 2.1-21.8 years). Within the cervical, thoracic, and lumbar spine regions, 3, 22, and 7 tumors arose, respectively. Median maximum tumor diameter was 5 cm (range, 3-19 cm). At diagnosis, 28 of 32 patients had motor, bowel, or bladder deficits. Chemotherapy was delivered according to contemporary North American and European interval-compressed regimens. Before radiation therapy, 14 patients underwent gross total resection, whereas 18 underwent a biopsy or subtotal resection with cord decompression. All patients were treated with proton therapy; 6 with hardware stabilization also received a component of intensity modulated photon therapy. Median prescription dose was 50.4 gray relative biological effectiveness (GyRBE; range, 45-55.8 GyRBE). Median maximum dose to the spinal cord was 50.2 GyRBE (range, 0-54.9 GyRBE). RESULTS: With a median follow-up of 4.1 years (range, 0.7-9.4 years), the 5-year local control, progression-free survival, and overall survival rates were 92%, 79%, and 85%, respectively. Ten of 30 living patients have residual motor, bowel, or bladder deficits. Overall, 22% of patients experienced Common Terminology Criteria for Adverse Events grade 3 late toxicity related to multimodality treatment: kyphosis (n = 4), esophagitis (n = 2), and chronic kidney disease (n = 1). No patients developed grade 4 or greater toxicity, new neurologic deficits, or second malignancy. CONCLUSIONS: Modern treatment advances may offer an improved therapeutic ratio for pediatric patients with spinal and paraspinal Ewing sarcoma. With appropriate management, most patients can be cured with recovery of long-term neurologic function and modest side effects.