The significance of margins in pediatric Non-Rhabdomyosarcoma soft tissue sarcomas. Consensus on surgical margin definition harmonization from the INternational Soft Tissue SaRcoma ConsorTium (INSTRuCT)

Background: Margin status following surgery in children, adolescents, and young adults with soft tissue sarcomas is controversial and has been defined differently by various specialties, with definitions changing over time and by cooperative group. The International Soft Tissue Sarcoma Consortium (INSTRuCT) is a collaboration of the Children's Oncology Group (COG) Soft Tissue Sarcoma Committee, European pediatric Soft Tissue sarcoma Study Group (EpSSG), and the European Cooperative Weichteilsarkom Studiengruppe (CWS) devoted to improving patient outcomes by pooling and mining cooperative group clinical trial data. Methods: The INSTRuCT non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) working group aimed to develop international harmonized recommendations regarding surgical margin assessment and definitions in children and adolescents with soft tissue tumors. Results and conclusion: This review addresses accepted principles and areas of controversy, including the perspectives of surgeons, pathologists, radiation oncologists, and pediatric oncologists, to develop a framework for building common guidelines for future research.