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NCT Number: NCT07188532

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

This clinical trial evaluates the effect of radiotherapy doses based on tumor size and tumor-specific characteristics (biologically-adapted) in treating patients with Ewing sarcoma. Radiotherapy uses high energy x-rays, particles, or radioactive seeds to kill tumor cells and shrink tumors. Conventional radiotherapy uses minimal imaging support to determine the positioning of radiotherapy. Hypofractionated radiotherapy delivers higher doses of radiotherapy over a shorter period of time and may kill more tumor cells and have fewer side effects. Dose-escalated radiotherapy uses doses that are higher than those used in conventional radiotherapy. Larger tumor sizes and other tumor-specific characteristics have been shown to be related to poorer outcomes. In addition, after dose-escalated radiotherapy, patients with larger tumors have demonstrated improved control of the disease at the primary tumor site. Giving biologically-adapted, dose-escalated radiotherapy may reduce the return of the cancer at the primary tumor site in patients with Ewing sarcoma with large tumors and other unfavorable characteristics. This clinical trial also evaluates the role of biomarkers in patients with Ewing sarcoma. Studying samples of blood and tumor tissue from patients with Ewing sarcoma in the laboratory may help doctors learn more about predicting the amount of disease and the likelihood of the cancer coming back.

Recruiting

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Key information

Age range

2 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Mayo Clinic in Arizona, Phoenix, Arizona, United States

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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
  • 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
  • Willing to provide biopsy sample to run Mayo Complete Solid Tumor Panel if tumor size is >= 8 cm

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

Treatment and study plan

Biospecimen Collection

Procedure

Undergo blood sample collection

Other names: Biological Sample Collection, Biospecimen Collected, Specimen Collection

Chemotherapy

Drug

Given chemotherapy

Other names: Chemo, Chemotherapy (NOS), Chemotherapy, Cancer, General

Computed Tomography

Procedure

Undergo CT or PET/CT

Other names: CAT, CAT Scan, Computed Axial Tomography, Computerized Axial Tomography, Computerized axial tomography (procedure), Computerized Tomography, Computerized Tomography (CT) scan, CT, CT Scan, Diagnostic CAT Scan, Diagnostic CAT Scan Service Type, tomography

Conventional Radiotherapy

Procedure

Undergo conventional radiotherapy

Other names: 2-Dimensional Conventional Radiation Therapy, 2D Conventional Radiotherapy, 2D Radiotherapy, 2D-RT, Radiation, 2D Conventional

Definitive Surgical Resection

Procedure

Undergo definitive surgical resection

Dose-escalated Radiation Therapy

Radiation

Undergo hypofractionated or conventional radiotherapy

Other names: Dose-escalated RT

Electronic Health Record Review

Other

Ancillary studies

external beam radiation therapy

Radiation

Undergo definitive radiotherapy

Other names: Definitive Radiation Therapy, EBRT, External Beam Radiation, External Beam Radiotherapy, External Beam Radiotherapy (conventional), External Beam RT, external radiation, External Radiation Therapy, external-beam radiation, Radiation, External Beam, Teleradiotherapy, Teletherapy, Teletherapy Radiation

Hypofractionated Radiation Therapy

Radiation

Undergo hypofractionated radiation therapy

Other names: Hypofractionated, Hypofractionated Radiotherapy, hypofractionation, Radiation, Hypofractionated

Magnetic Resonance Imaging

Procedure

Undergo MRI

Other names: Magnetic Resonance, Magnetic Resonance Imaging (MRI), Magnetic resonance imaging (procedure), Magnetic Resonance Imaging Scan, Medical Imaging, Magnetic Resonance / Nuclear Magnetic Resonance, MR, MR Imaging, MRI, MRI Scan, MRIs, NMR Imaging, NMRI, Nuclear Magnetic Resonance Imaging, sMRI, Structural MRI

Positron Emission Tomography

Procedure

Undergo PET/CT

Other names: Medical Imaging, Positron Emission Tomography, PET, PET Scan, Positron emission tomography (procedure), Positron Emission Tomography Scan, Positron-Emission Tomography, PT

Questionnaire Administration

Other

Ancillary studies

radiation therapy

Radiation

Undergo hypofractionated or conventional standard radiotherapy

Other names: Cancer Radiotherapy, Energy Type, ENERGY_TYPE, Irradiate, Irradiated, Irradiation, Radiation, Radiation Therapy, NOS, Radiotherapeutics, Radiotherapy, RT, Therapy, Radiation

Primary outcomes

  1. Reduction in local failure for patients with large tumors (Cohort A)

    Time frame: Up to 2 years

    Large tumors defined as ≥ 8cm. Will be compared to the historical control of 14.3%. Local failure will be defined per the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.

Secondary outcomes

  1. Incidence of targeted, late grade 3 or greater adverse events (Cohort A)

    Time frame: Up to 1 year after completion of local therapy

    Assessed per RECIST version 1.1.

  2. Event-free survival (Cohort A)

    Time frame: Up to 1 year after completion of local therapy

    Event-free survival (EFS) is defined as the time from study entry to any progression of disease or recurrence of disease or death from any cause, whichever occurs first.

  3. Time to progression (Cohort A)

    Time frame: Up to 1 year after completion of local therapy

    Will be calculated descriptively, via frequencies and percentages at various timepoints of interest, including the 1-year local control rate.

  4. Overall survival (Cohort A)

    Time frame: Up to 1 year after completion of local therapy

    Overall survival (OS) is defined as the time from study entry to death from any cause, estimated using the Kaplan-Meier method.

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Trials Referral Office

CONTACT

[email protected]

855-776-0015

Sponsors and collaborators

Lead sponsor

Mayo Clinic

Other

Registry information

Official study title

Biologically-Adapted, Dose-Escalated Accelerated Radiotherapy for Ewing Sarcoma (BEAR)

Acronym: BEAR

Important dates

Study start
2025
Primary completion
2029
Study completion
2029
First posted
Sep 23, 2025
Registry last updated
Jun 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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