الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Summary Ewing sarcoma is the second most common bone cancer in adolescents and young adults (after osteosarcoma) consisting of 34% of malignant bone tumors. Ewing’s sarcomas, unlike osteosarcomas, tend to arise from the diaphyseal rather than the metaphyseal portion. The most common sites of primary Ewing’s sarcoma are the pelvic bones, the long bones of the lower extremities, and the bones of the chest wall. Primary metastases in lungs, bone, bone marrow, or combinations of them are detectable in about 25% of patients. Because most patients with apparently localized disease at diagnosis have occult metastatic disease, multidrug chemotherapy and local disease control with surgery and/or radiation therapy is indicated in the treatment of all patients as in figure 5. Current regimens for the treatment of localized Ewing sarcoma achieve event-free survival (EFS) and overall survival (OS) of approximately 70% at 5 years after diagnosis. Computed tomography in association with PET/CT has been utilized as a powerful tool to allow for such a differentiation with high sensitivity and specificity, since it is a hybrid method, providing anatomical detailing of the lesions and glycolytic metabolism evaluation (habitually increased in such lesions). In addition, one proposes that the degree of 18F-FDG uptake by Ewing’s tumors may have a prognostic value, predicting the patient’s response to treatment and indicating the initial stage of the disease. The aim of this work is to evaluate of the role of F-18 FDG PET/CT in the assessment of response to neo-adjuvant chemotherapy for Ewing sarcoma and correlation with tumor necrosis and overall survival 1 year after