Treatment lengths vary depending on location and stage of the disease at diagnosis. Radical chemotherapy may be as short as six treatments at three-week cycles, but most people undergo chemotherapy for 6–12 months and radiation therapy for 5–8 weeks. Radiotherapy has been used for localized disease. The tumor has a unique property of being highly sensitive to radiation, sometimes acknowledged by the phrase "melting like snow", but the main drawback is that it recurs dramatically after some time.Antisense oligodeoxynucleotides have been proposed as possible treatment by down-regulating the expression of the oncogenic fusion protein associated with the development of Ewing sarcoma resulting from the EWS-ETS gene translocation. In addition, the synthetic retinoid derivative fenretinide (4-hydroxy(phenyl)retinamide) has been reported to induce high levels of cell death in Ewing sarcoma cell lines in vitro and to delay growth of xenografts in in vivo mouse models.In most pediatric cancers including sarcoma, proton beam radiation (also known as proton therapy) delivers an equally effective dose to the tumor with less damage to the surrounding normal tissue compared to photon radiation. Prognosis
Staging attempts to distinguish people with localized from those with metastatic disease. The most common areas of metastasis are the lungs, bone and bone marrow with less common areas of metastasis being the lymph nodes, liver and brain.
Medical imaging
On conventional radiographs, typical findings of Ewing sarcoma consist of multiple confluent lytic bone lesions that have a "moth eaten" pattern due to permeative destruction of bone. There will also be a displaced periosteum as the new sub-periosteal layer of bone begins to grow on top of the tumor. This raised or displaced periosteum is consistent with the classic radiographic finding of the Codman triangle. The proliferative reaction of bone can also create delicate laminations constituting the periosteal layers and giving the radiographic appearance of an onion peel. Plain films add valuable information in the initial evaluation or screening. The wide zone of transition (e.g. permeative) is the most useful plain film characteristic in differentiation of benign versus aggressive or malignant lytic lesions. Magnetic resonance imaging (MRI) should be routinely used in the work-up of malignant tumors. It will show the full bony and soft tissue extent and relate the tumor to other nearby anatomic structures (e.g. vessels). Gadolinium contrast is not necessary as it does not give additional information over noncontrast studies, though some current researchers argue that dynamic, contrast-enhanced MRI may help determine the amount of necrosis within the tumor, thus help in determining response to treatment prior to surgery.Computed axial tomography (CT) can also be used to define the extraosseous extent of the tumor, especially in the skull, spine, ribs, and pelvis. Both CT and MRI can be used to follow response to radiation and/or chemotherapy.