An interventional study of Biospecimen Collection and Chemotherapy in Ewing Sarcoma and Round Cell Sarcoma With EWSR1-non-ETS Fusion, sponsored by Mayo Clinic. Recruiting at 2 sites in United States. Open to participants aged 2 Years and older. Per ClinicalTrials.gov, last updated 2026-10-06.
Sponsored by Mayo Clinic · Not applicable, Interventional, and Treatment
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.
250 studies on the registry are indexed under Sarcoma, Ewing; 69 are open to participants now.
This study's planned enrollment of 170 is above the median of 36 across 204 interventional studies indexed under Sarcoma, Ewing.
Browse Sarcoma, Ewing studies →Mayo Clinic is the lead sponsor of 3,269 studies on the registry; 672 are open to participants now.
Of its 452 completed or terminated interventional studies of FDA-regulated products, 321 (71%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Receiving any 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
Any of the following:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Karnofsky performance status (KPS)
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients may receive SOC chemotherapy every 2 weeks for at least 3 cycles prior to radiotherapy. Patients then undergo hypofractionated or conventional dose-escalated radiotherapy daily, excluding weekends and holidays, for 25-36 treatment fractions in the absence of disease progression or unacceptable toxicity. Patients may also receive consolidation chemotherapy after completion of radiotherapy and/or surgical resection. Patients also undergo blood sample collection throughout the study. Additionally, patients may also undergo CT, PET/CT, and MRI with or without CT throughout the study at treating clinician's discretion.
Procedure: Biospecimen Collection · Drug: Chemotherapy · Procedure: Computed Tomography · Procedure: Conventional Radiotherapy · Procedure: Definitive Surgical Resection · Radiation: Dose-escalated Radiation Therapy · Other: Electronic Health Record Review · Radiation: Hypofractionated Radiation Therapy · Procedure: Magnetic Resonance Imaging · Procedure: Positron Emission Tomography · Other: Questionnaire Administration
Patients may receive SOC chemotherapy every 2 weeks for at least 3 cycles prior to radiotherapy. Patients then undergo hypofractionated or conventional standard dose radiotherapy daily, excluding weekends and holidays, for 25-31 treatment fractions in the absence of disease progression or unacceptable toxicity. Patients may also receive consolidation chemotherapy after completion of radiotherapy and/or surgical resection. Patients also undergo blood sample collection throughout the study. Additionally, patients may also undergo CT, PET/CT, and MRI with or without CT throughout the study at treating clinician's discretion.
Procedure: Biospecimen Collection · Drug: Chemotherapy · Procedure: Computed Tomography · Procedure: Conventional Radiotherapy · Procedure: Definitive Surgical Resection · Other: Electronic Health Record Review · Radiation: Hypofractionated Radiation Therapy · Procedure: Magnetic Resonance Imaging · Procedure: Positron Emission Tomography · Other: Questionnaire Administration · Radiation: Radiation Therapy
Patients may receive SOC chemotherapy every 2 weeks for at least 3 cycles prior to radiotherapy. Patients with tumor size \< 8cm at diagnosis undergo definitive radiotherapy or surgical resection. Patients may also receive consolidation chemotherapy after completion of definitive radiotherapy or surgical resection. Patients also undergo blood sample collection throughout the study. Additionally, patients may also undergo CT, PET/CT, and MRI with or without CT throughout the study at treating clinician's discretion.
Procedure: Biospecimen Collection · Drug: Chemotherapy · Procedure: Computed Tomography · Procedure: Definitive Surgical Resection · Other: Electronic Health Record Review · Radiation: External Beam Radiation Therapy · Procedure: Magnetic Resonance Imaging · Procedure: Positron Emission Tomography · Other: Questionnaire Administration
Patients may receive SOC chemotherapy every 2 weeks for at least 3 cycles prior to radiotherapy. Patients undergo radiotherapy before or after undergoing definitive surgical resection. Patients may also receive consolidation chemotherapy after completion of definitive radiotherapy and surgical resection. Patients also undergo blood sample collection throughout the study. Additionally, patients may also undergo CT, PET/CT, and MRI with or without CT throughout the study at treating clinician's discretion.
Procedure: Biospecimen Collection · Drug: Chemotherapy · Procedure: Computed Tomography · Procedure: Conventional Radiotherapy · Procedure: Definitive Surgical Resection · Other: Electronic Health Record Review · Radiation: External Beam Radiation Therapy · Radiation: Hypofractionated Radiation Therapy · Procedure: Magnetic Resonance Imaging · Procedure: Positron Emission Tomography · Other: Questionnaire Administration · Radiation: Radiation Therapy
Undergo blood sample collection
Also known as: Biological Sample Collection, Biospecimen Collected, Specimen Collection
Given chemotherapy
Also known as: Chemo, Chemotherapy (NOS), Chemotherapy, Cancer, General
Undergo CT or PET/CT
Also known as: 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
Undergo conventional radiotherapy
Also known as: 2-Dimensional Conventional Radiation Therapy, 2D Conventional Radiotherapy, 2D Radiotherapy, 2D-RT, Radiation, 2D Conventional
Undergo definitive surgical resection
Undergo hypofractionated or conventional radiotherapy
Also known as: Dose-escalated RT
Ancillary studies
Undergo definitive radiotherapy
Also known as: 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
Undergo hypofractionated radiation therapy
Also known as: Hypofractionated, Hypofractionated Radiotherapy, hypofractionation, Radiation, Hypofractionated
Undergo MRI
Also known as: 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
Undergo PET/CT
Also known as: Medical Imaging, Positron Emission Tomography, PET, PET Scan, Positron emission tomography (procedure), Positron Emission Tomography Scan, Positron-Emission Tomography, PT
Ancillary studies
Undergo hypofractionated or conventional standard radiotherapy
Also known as: Cancer Radiotherapy, Energy Type, ENERGY_TYPE, Irradiate, Irradiated, Irradiation, Radiation, Radiation Therapy, NOS, Radiotherapeutics, Radiotherapy, RT, Therapy, Radiation
Reduction in local failure for patients with large tumors (Cohort A)
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.
Time frame: Up to 2 years
Incidence of targeted, late grade 3 or greater adverse events (Cohort A)
Assessed per RECIST version 1.1.
Time frame: Up to 1 year after completion of local therapy
Event-free survival (Cohort A)
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.
Time frame: Up to 1 year after completion of local therapy
Time to progression (Cohort A)
Will be calculated descriptively, via frequencies and percentages at various timepoints of interest, including the 1-year local control rate.
Time frame: Up to 1 year after completion of local therapy
Overall survival (Cohort A)
Overall survival (OS) is defined as the time from study entry to death from any cause, estimated using the Kaplan-Meier method.
Time frame: Up to 1 year after completion of local therapy
Started Dec 2025 (actual). Primary completion is estimated for Aug 2033, 92 months after the start.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 5, 2026: start Nov 2025 → Dec 2025, primary completion Dec 2029 → Aug 2033 and completion Dec 2029 → Aug 2033.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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