Systematic review and meta-analysis of photon radiotherapy versus proton beam therapy for pediatric Ewing sarcoma: TRP-Ewing sarcoma 2024

Abstract Background: Advances in multimodal treatment strategies and chemotherapy have led to improved outcomes for patients with Ewing sarcoma (EWS). Proton beam therapy (PBT) has increasingly been utilized in pediatric oncology to minimize late toxicities associated with conventional treatments; however, studies specifically addressing the use of PBT in EWS remain limited. Methods: We conducted a meta-analysis to compare the efficacy of photon radiotherapy (RT) and PBT in the treatment of pediatric EWS. We analyzed English-language articles published between 1990 and 2022 that included at least 10 patients and described RT treatment protocols. The primary endpoints were overall survival (OS) and local control (LC). Results: A total of 38 studies from 36 articles (8 reporting PBT and 30 reporting photon RT) were included in the meta-analysis. PBT showed better 5-year OS and 4- and 3-year LC rates compared to photon RT. In analyses restricted to studies published since 2015, only the 5-year OS remained significantly different. No associations were found between OS or LC and variables such as age, sex ratio, or the rate of concurrent chemotherapy or surgery. Discussion: The observed differences across the entire study period may be attributed to improvements in treatment protocols, including interval-compressed chemotherapy, and recent advancements in supportive care and radiation technology, which could have influenced outcomes. Conclusion: PBT appears to be non-inferior to photon RT in the treatment of pediatric EWS. Further studies are needed to assess long-term outcomes and the potential treatment-related toxicities of PBT.