Amputation, Antineoplastic Agents, Antineoplastic Combined Chemotherapy Protocols, Biopsy, Bone Neoplasms, Chemoradiotherapy, Adjuvant, Chemotherapy, Adjuvant, Clinical Trials as Topic, Drug Resistance, Neoplasm, Humans, Incidence, Magnetic Resonance Imaging, Medical Oncology, Neoplasm Recurrence, Local, Neoplasm Staging, Positron Emission Tomography Computed Tomography, Practice Guidelines as Topic, Prognosis, Sarcoma, Ewing, Survival Rate