Whole Abdominal Radiotherapy in Bone and Soft Tissue Sarcomas: Indications, Techniques, Clinical Outcomes, and Future Directions

Managing bone and soft tissue sarcomas at high risk of intra-abdominal spread remains clinically challenging, and whole abdominal radiotherapy (WART) has become a pivotal locoregional component of multimodal therapy. For desmoplastic small round cell tumor (DSRCT)—the primary indication for WART—our practice prioritizes integrating WART with complete cytoreductive surgery and alkylator-based chemotherapy, with intensity-modulated radiotherapy (IMRT) or helical tomotherapy strongly recommended as preferred techniques due to their significant reduction in hematologic and gastrointestinal toxicity versus conventional 2D radiotherapy while preserving target coverage. For other subtypes (peritoneal rhabdomyosarcoma, Ewing sarcoma, myxoid liposarcoma), WART should be individualized: considered for confirmed peritoneal dissemination, residual disease post-chemotherapy, or incomplete resection, but avoided in extensive distant metastases. Future paradigms must optimize benefit-to-toxicity ratios, including routine proton/carbon ion therapy for pediatric/young adult patients to minimize late effects (e.g., growth abnormalities, infertility), exploration of WART combinations with targeted agents (e.g., IGF-1R inhibitors) or immunotherapies (e.g., PD-1/PD-L1 inhibitors) in prospective trials given promising preclinical/early clinical data, and use of molecular profiling and circulating tumor DNA (ctDNA) monitoring to guide patient selection and timely treatment adjustments. Long-term follow-up is essential for all patients to monitor late toxicities (e.g., small bowel obstruction, radiation nephritis) and secondary malignancies. In summary, WART is a cornerstone of curative-intent treatment for selected intra-abdominal sarcomas, but requires rigorous patient selection, advanced planning, and integration with systemic therapies, with continued international collaboration and trials critical to refining its role and improving outcomes for these rare, aggressive malignancies.