Biologically-Adapted, Dose-Escalated Radiotherapy for the Treatment of Ewing Sarcoma, BEAR Trial

Inclusion Criteria: PRE-REGISTRATION: INCLUSION CRITERIA * Histological confirmation of Ewing sarcoma, including both skeletal and extra-skeletal primary tumors. Patients with "Ewing-like" sarcoma may be eligible if patients are planned to be treated per Ewing treatment paradigms, as defined in this clinical trial REGISTRATION: INCLUSION CRITERIA * Patients of age ≥ 2 years are eligible for the study * Lansky or Karnofsky performance status ≥ 70 * Ability to provide written informed consent and complete questionnaire(s) by themselves or with assistance * Willing to provide blood samples for correlative research purposes * COHORT A ONLY: Willing to provide biopsy sample to run Mayo Complete Solid Tumor Panel Exclusion Criteria: REGISTRATION: EXCLUSION CRITERIA * Prior chemotherapy or radiotherapy that, in the opinion of the treating medical oncologist or radiation oncologist, is considered to interfere with the current treatment or measurement of outcomes * Receiving any investigational agent which would be considered as a treatment for the primary neoplasm that is considered by the investigator to interfere with the current treatment or measurement of outcomes * Note: Co-enrollment on another clinical trial is allowed per the treating radiation oncologist's discretion * Other active malignancy ≤ 1 year prior to registration that is considered by the investigator to interfere with the current treatment or measurement of outcomes * Patients that have severe co-morbid systemic illness or other disease which would interfere significantly with the current treatment or measurement of outcomes * Patients that have active uncontrolled systemic infection, symptomatic congestive heart failure, unstable angina, cardiac arrhythmia, or psychiatric illness or social situation that would limit study adherence * Any of the following: * Pregnant patients * Nursing patients