The role of radiotherapy in local control of nonextremity Ewing sarcomas.

To evaluate the results of radiotherapy and the prognostic factors affecting local control in nonextremity Ewing sarcomas.Between 1995 and 2011, 44 patients with nonextremity Ewing sarcomas were treated with radiotherapy. Tumor localizations were pelvis in 23, spine in 13, thoracic region in 5, and cranium in 3 patients. Tumor size was ≥8 cm in 56.8% of patients. Distant metastases were present in 19 of the patients at the time of diagnosis (43.1%). All patients were treated with 12 weeks of neoadjuvant chemotherapy followed by surgery and radiotherapy (45-54 Gy) or radiotherapy alone (54-64.8 Gy). Radiotherapy was applied due to microscopic residue (R1) in 5 patients after the operation and macroscopic tumor in 39 patients (macroscopic residue [R2] and nonresectable tumor).Median follow-up was 49 months (range 9-195). Local failures developed in 7 patients (15.9%) and local control at 5 years was 81.4%. Local recurrence was detected in 6 patients (6/38) who did not have residual tumor after RT. Progression was detected in 1 patient (1/6) who had residual tumor. All those patients with local failure experienced further distant metastases. Possible prognostic factors such as age (≤17 vs >17), tumor localization, tumor volume (≤8 cm vs >8 cm), and M status at diagnosis (0 vs 1) were not related to local control.Radiotherapy, either alone or adjuvant to surgery, provides local control in 80% of nonextremity Ewing sarcomas and plays an important role in treatment.