Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation

Purpose: Dose escalation for definitive radiation therapy (DE-RT) in larger Ewing sarcomas (ESs) is associated with a lower risk of local recurrence. We report treatment and toxicity outcomes in ES tumors treated with DE-RT, including hypofractionated approaches and size stratification of analysis....

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Main Authors: Taylor M. Weiskittel, MD, PhD, William S. Harmsen, MS, Anita Mahajan, MD, Ivy A. Petersen, MD, Michael G. Haddock, MD, Wendy Allen-Rhoades, MD, PhD, Steven I. Robinson, MD, Nadia N. Laack, MD, Safia K. Ahmed, MD
Format: Article
Language:English
Published: Elsevier 2025-08-01
Series:Advances in Radiation Oncology
Online Access:http://www.sciencedirect.com/science/article/pii/S2452109425001071
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author Taylor M. Weiskittel, MD, PhD
William S. Harmsen, MS
Anita Mahajan, MD
Ivy A. Petersen, MD
Michael G. Haddock, MD
Wendy Allen-Rhoades, MD, PhD
Steven I. Robinson, MD
Nadia N. Laack, MD
Safia K. Ahmed, MD
author_facet Taylor M. Weiskittel, MD, PhD
William S. Harmsen, MS
Anita Mahajan, MD
Ivy A. Petersen, MD
Michael G. Haddock, MD
Wendy Allen-Rhoades, MD, PhD
Steven I. Robinson, MD
Nadia N. Laack, MD
Safia K. Ahmed, MD
author_sort Taylor M. Weiskittel, MD, PhD
collection DOAJ
description Purpose: Dose escalation for definitive radiation therapy (DE-RT) in larger Ewing sarcomas (ESs) is associated with a lower risk of local recurrence. We report treatment and toxicity outcomes in ES tumors treated with DE-RT, including hypofractionated approaches and size stratification of analysis. Methods and Materials: A retrospective review of ES patients treated with DE-RT to doses ≥55.8 Gy was performed. Local failure (LF) with death as a competing risk was assessed. Maximally selected rank statistics were used to determine the optimal stratification of patients by survival using tumor size measurements. Results: In total, 47 patients were analyzed. Twenty-eight patients (59.6%) received DE-RT, of which 6 received hypofractionation. For DE-RT, median equivalent dose in 2 Gy fraction for α/β = 10 was 60 Gy (range, 56.2-62) with conventional fractionation and 62.2 Gy (range, 56.5-67.1) with hypofractionation. Empirically derived size cutoffs identified a subgroup of ultralarge tumors at higher risk of LF defined as >11.8 cm in the longest direction, 569.2 cm3 prechemotherapy volume, or 288.9 cm3 postchemotherapy volume. Five-year cumulative incidence of LF was lower in patients treated with DE-RT at 11.7% (95% CI, 3.16%-43.6%) versus 35.6% for non-DE-RT (95% CI, 17.4%-72.61%; P = .098). Multivariate analysis showed trends toward DE-RT benefiting tumors of all sizes and stages. Conclusions: DE-RT was associated with a trend toward better LF in all tumors without toxicity or plan quality changes. Ultralarge tumors demonstrated poor LF rates and necessitate further study.
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spelling doaj-art-9cc8aa88884e48929b78d7d6ca7293a02025-08-20T03:29:09ZengElsevierAdvances in Radiation Oncology2452-10942025-08-0110810182010.1016/j.adro.2025.101820Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and FractionationTaylor M. Weiskittel, MD, PhD0William S. Harmsen, MS1Anita Mahajan, MD2Ivy A. Petersen, MD3Michael G. Haddock, MD4Wendy Allen-Rhoades, MD, PhD5Steven I. Robinson, MD6Nadia N. Laack, MD7Safia K. Ahmed, MD8Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota; Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester, MinnesotaBiomedical Statistics and Informatics, Mayo Clinic, Rochester, MinnesotaRadiation Oncology, Mayo Clinic, Rochester, MinnesotaRadiation Oncology, Mayo Clinic, Rochester, MinnesotaRadiation Oncology, Mayo Clinic, Rochester, MinnesotaPediatric and Adolescent Medicine, Mayo Clinic, Rochester, MinnesotaMedical Oncology, Mayo Clinic, Rochester, MinnesotaRadiation Oncology, Mayo Clinic, Rochester, MinnesotaRadiation Oncology, Mayo Clinic, Phoenix, Arizona; Corresponding author: Safia Ahmed, MDPurpose: Dose escalation for definitive radiation therapy (DE-RT) in larger Ewing sarcomas (ESs) is associated with a lower risk of local recurrence. We report treatment and toxicity outcomes in ES tumors treated with DE-RT, including hypofractionated approaches and size stratification of analysis. Methods and Materials: A retrospective review of ES patients treated with DE-RT to doses ≥55.8 Gy was performed. Local failure (LF) with death as a competing risk was assessed. Maximally selected rank statistics were used to determine the optimal stratification of patients by survival using tumor size measurements. Results: In total, 47 patients were analyzed. Twenty-eight patients (59.6%) received DE-RT, of which 6 received hypofractionation. For DE-RT, median equivalent dose in 2 Gy fraction for α/β = 10 was 60 Gy (range, 56.2-62) with conventional fractionation and 62.2 Gy (range, 56.5-67.1) with hypofractionation. Empirically derived size cutoffs identified a subgroup of ultralarge tumors at higher risk of LF defined as >11.8 cm in the longest direction, 569.2 cm3 prechemotherapy volume, or 288.9 cm3 postchemotherapy volume. Five-year cumulative incidence of LF was lower in patients treated with DE-RT at 11.7% (95% CI, 3.16%-43.6%) versus 35.6% for non-DE-RT (95% CI, 17.4%-72.61%; P = .098). Multivariate analysis showed trends toward DE-RT benefiting tumors of all sizes and stages. Conclusions: DE-RT was associated with a trend toward better LF in all tumors without toxicity or plan quality changes. Ultralarge tumors demonstrated poor LF rates and necessitate further study.http://www.sciencedirect.com/science/article/pii/S2452109425001071
spellingShingle Taylor M. Weiskittel, MD, PhD
William S. Harmsen, MS
Anita Mahajan, MD
Ivy A. Petersen, MD
Michael G. Haddock, MD
Wendy Allen-Rhoades, MD, PhD
Steven I. Robinson, MD
Nadia N. Laack, MD
Safia K. Ahmed, MD
Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
Advances in Radiation Oncology
title Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
title_full Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
title_fullStr Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
title_full_unstemmed Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
title_short Definitive Radiation Therapy for Ewing Sarcoma: Outcomes Based on Tumor Volume, Dose, and Fractionation
title_sort definitive radiation therapy for ewing sarcoma outcomes based on tumor volume dose and fractionation
url http://www.sciencedirect.com/science/article/pii/S2452109425001071
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