Background: Although multidisciplinary therapies have improved local control and overall survival in Ewing sarcoma (ES), the prognosis of pelvic lesions remains markedly worse than that of limb ES.
Methods: We retrospectively evaluated the influence of the type of local treatment, margins, necrosis and sacrum involvement on overall survival (OS) and disease-free survival (DFS) in a series of 21 non-metastatic pelvic ES.
Results: The average follow-up was 46.3 months (range 3-156). Only one patient had recurrence, at 11 months after surgery. Eight patients showed pulmonary metastasis and five showed bone metastases. Necrosis was the only significant prognostic factor for overall survival at 5 years (p=0.0132) and disease-free survival (p=0.0086). Overall survival at 5 years was 40.1%.
Conclusion: Local control in pelvic Ewing sarcoma is comparable for patients treated with surgery (S), surgery plus radiotherapy (S/RT), or definitive radiotherapy (RT). The combination of surgery plus radiotherapy could be indicated in cases of large tumor, a poor necrosis response (< 90%), or an inadequate margin with involvement of the sacrum. A poor response to neoadjuvant therapy is a significant risk factor for both local control and overall survival.