Ewing Sarcoma Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Ewing Sarcoma: Localized Tumors
If a very young child has Ewing sarcoma, surgery may be a less morbid therapy than radiation therapy because of the retardation of bone growth caused by radiation. Another potential benefit for surgical resection of the primary tumor is information concerning the amount of necrosis in the resected tumor. Patients with residual viable tumor in the resected specimen have a worse outcome than those with complete necrosis. In a French Ewing study (EW88), EFS for patients with less than 5% viable tumor, 5% to 30% viable tumor, and more than 30% viable tumor was 75%, 48%, and 20%, respectively. European investigators are studying whether treatment intensification (i.e., high-dose chemotherapy with stem cell rescue) will improve outcome for patients with a poor histologic response. Radiation therapy should be employed for patients who do not have a surgical option that preserves function and should be used for patients whose tumors have been excised but with inadequate margins. Pathologic fracture at the time of diagnosis does not preclude surgical resection and is not associated with adverse outcome.
Radiation therapy should be delivered in a setting in which stringent planning techniques are applied by those experienced in the treatment of Ewing sarcoma. Such an approach will result in local control of the tumor with acceptable morbidity in most patients.[1,2,20] The radiation dose may be adjusted depending on the extent of residual disease after the initial surgical procedure. Radiation therapy is generally administered in fractionated doses totaling approximately 55.8 Gy to the prechemotherapy tumor volume. A randomized study of 40 patients with Ewing sarcoma using 55.8 Gy to the prechemotherapy tumor extent with a 2 cm margin compared with the same total-tumor dose following 39.6 Gy to the entire bone showed no difference in local control or EFS. Hyperfractionated radiation therapy has not been associated with improved local control or decreased morbidity.
Comparison of proton-beam radiation therapy and intensity-modulated radiation therapy (IMRT) treatment plans has shown that proton-beam radiation therapy can spare more normal tissue adjacent to Ewing sarcoma primary tumors than IMRT. Follow-up remains relatively short, and there are no data available to determine if the reduction in dose to adjacent tissue will result in improved functional outcome or reduce the risk of secondary malignancy. Because patient numbers are small and follow-up is relatively short, it is not possible to determine if the risk of local recurrence might be increased by reducing radiation dose in tissue adjacent to the primary tumor.
Higher rates of local failure are seen in patients older than 14 years who have tumors more than 8 cm in length. A retrospective analysis of patients with Ewing sarcoma of the chest wall compared patients who received hemithorax radiation therapy with those who received radiation therapy to the chest wall only. Patients with pleural invasion, pleural effusion, or intraoperative contamination were assigned to hemithorax radiation therapy. EFS is longer for patients who received hemithorax radiation, but the difference was not statistically significant. In addition, most patients with primary vertebral tumors did not receive hemithorax radiation and had a lower probability for EFS.