Identification of patients with localized Ewing sarcoma at higher risk for local failure: A report from the Children’s Oncology Group

Publication date: Available online 24 August 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Safia K. Ahmed, R. Lor Randall, Steven G. DuBois, William S. Harmsen, Mark Krailo, Karen J. Marcus, Katherine A. Janeway, David S. Geller, Joel I. Sorger, Richard B. Womer, Linda Granowetter, Holcombe E. Grier, Richard G. Gorlick, Nadia N.I. Laack
PurposeTo identify clinical and treatment variables associated with a higher risk of local failure in Ewing sarcoma patients treated on recent Children's Oncology Group protocols.Methods and MaterialsData for 956 patients treated with ifosfamide and etoposide based chemotherapy on INT-0091, INT-0154, and AEWS0031 were analyzed. Local treatment modalities were defined as surgery, definitive radiotherapy (RT), or surgery+radiation (S+RT). Five-year cumulative incidence of local failure was determined.ResultsThe local failure rate for the entire cohort was 7.3%, with a 3.9% rate for surgery, 15.3% for RT (p<0.01), and 6.7% for S+RT (p=0.12). The local failure incidence was 5.4% for extremity tumors, 13.2% for pelvis tumors (p<0.01), 5.3% for axial non-spine tumors (p=0.90), 9.1% for extraskeletal tumors (p=0.08), and 3.6% for spine tumors (p=0.49). The incidence of local failure was 14.8% for extremity tumors and 22.4% for pelvis tumors treated with RT, compared to 3.7% for extremity tumors and 3.9% for pelvis tumors treated with surgery (p≤0.01). There was no difference in local failure incidence by local treatment modality for axial non-spine, spine, and extraskeletal tumors. The local failure incidence was 11.9% in patients ≥18 years versus 6.7% in patients <18 years (p=0.02). Age ≥18 years (Hazard ratio 1.9, p=0.04) and treatment with RT (Hazard ratio 2.40, p<0.01) remained independent prognostic factors for higher local failure incidence on multivariate analysis. Tumor size (</≥ 8 centimeters) was available in 40% of patients and did not correlate with local failure incidence.ConclusionsLocal tumor control is excellent and similar between surgery and RT for axial non-spine, spine, and extraskeletal tumors. Age ≥18 years and use of RT, primarily for pelvis and extremity tumors, are associated with the highest risk of local failure. Further efforts should focus on improving outcomes for these patients.

Teaser

Our analysis of local tumor control outcomes in 956 Ewing sarcoma patients demonstrates age ≥18 years and use of definitive radiotherapy, primarily for pelvis and extremity tumors, are associated with the highest risk of local failure. Local tumor control is excellent and similar between surgery and definitive radiotherapy for axial non-spine, spine, and soft tissue extraskeletal tumors.


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