Abstract
Radiation therapy (RT) is advocated in the multimodal treatment of high-grade soft tissue sarcoma (STS), but its role may be less clear in chemotherapy-sensitive STS such as extraskeletal Ewing sarcoma (EES). The purpose of this study was to determine the role of RT on overall survival (OS) in localized EES adult patients treated with chemotherapy and surgery. Adult patients diagnosed with EES and reported to the National Cancer Database from 2004 to 2014 were evaluated. All patients were treated with surgical resection. Patient demographics, tumor characteristics, treatments received, resection margins, and survival were examined for the 232 patients identified. Using multivariate analysis and Cox proportional hazard analysis, predictors of OS were determined. In the overall cohort, 40 percent of patients received RT and 78 percent received chemotherapy, with 31 percent receiving both. The addition of RT to the patients receiving surgery + chemotherapy did not improve OS (p < 0.05). Twenty-four percent of patients who achieved R0 resection after surgery still received RT without any improvement in OS. Patients treated at community cancer centers were more likely to receive additional RT compared with Comprehensive Cancer Centers (p < 0.05). In adult EES patients with localized disease treated with chemotherapy and surgery, the addition of RT does not improve overall survival.
Highlights
Ewing sarcoma consists of a group of tumors characterized by morphologically similar round-cell neoplasms derived from undifferentiated mesenchymal cells with the potential for neuroectodermal differentiation [1,2,3,4]
Patients with Extraskeletal Ewing sarcoma (EES) were treated with a rhabdomyosarcoma protocol but current evidence suggests that these patients benefit from skeletal Ewing sarcoma protocols instead [20, 21]. e National Comprehensive Cancer Network (NCCN) does not differentiate the treatment of EES from skeletal Ewing sarcoma [22]
Radiation-associated complications such as joint contracture, muscle atrophy, pathologic fractures, and secondary malignancies occurring in 10 percent to up to 63 percent of patients receive radiation therapy (RT) for sarcomas [2]. e role of RT in adult soft tissue sarcoma (STS) has recently been reviewed, with a large-scale National Cancer Database (NCDB) analysis demonstrating improvements in R0 resection and overall survival (OS) in STS [30]. e analysis did not differentiate between histologic types of STS. is is important as EES is an STS with an above average favorable response to chemotherapy [8]. e histologic specific impact of RT on survival, especially in chemotherapy-sensitive diseases such as EES, remains unclear
Summary
Ewing sarcoma consists of a group of tumors characterized by morphologically similar round-cell neoplasms derived from undifferentiated mesenchymal cells with the potential for neuroectodermal differentiation [1,2,3,4]. E largest studies to investigate EES compared outcomes relative to skeletal Ewing sarcoma without particular analysis of treatment modalities specific to EES [7, 12,13,14,15,16,17,18,19]. Patients with EES were treated with a rhabdomyosarcoma protocol but current evidence suggests that these patients benefit from skeletal Ewing sarcoma protocols instead [20, 21]. E National Comprehensive Cancer Network (NCCN) does not differentiate the treatment of EES from skeletal Ewing sarcoma [22]. Standard of care guidelines for treatment of osseous and extraosseous Ewing sarcoma include multiagent chemotherapy prior to local control treatment for nonmetastatic disease [23]. Ewing sarcoma is more common in young patients where the risk of RT-associated secondary
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