Article Summary
A new European guideline provides 32 consensus-based imaging recommendations for osteosarcoma and Ewing sarcoma to standardize care across pediatric and adult populations. The guideline aims to reduce variation between institutions, improve treatment response assessment, and enable better research collaboration while identifying major evidence gaps in metastatic staging and surveillance strategies.
- The European guideline offers 32 recommendations for imaging osteosarcoma and Ewing sarcoma across pediatric and adult care settings.
- Developed by 36 multidisciplinary experts from the FOSTER consortium, Euro Ewing Consortium, European Society of Paediatric Radiology, and EANM.
- Major evidence gaps remain in metastatic staging methods, with no consensus on whether whole-body MRI, bone scintigraphy, or PET/CT is superior.
- No metabolic imaging index or MRI parameter has been validated as a consistent predictor of treatment response or survival.
- Harmonized imaging protocols enable easier comparison of serial examinations across institutions and facilitate pooling of research data from multiple centers.
Osteosarcoma and Ewing sarcoma are rare cancers that occur most often in children, adolescents, and young adults. Because many institutions see relatively few cases, individual centers can struggle to establish consistent imaging pathways or generate large enough datasets on their own.
Imaging plays a central role throughout the management of both diseases, from staging and treatment-response assessment to surveillance after treatment. Until now, however, no international consensus had defined the optimal imaging modalities and schedules across both pediatric and adult populations.
A new joint European guideline could help change that. It offers 32 recommendations for imaging osteosarcoma and Ewing sarcoma across pediatric and adult care, while also exposing major evidence gaps in metastatic staging, treatment-response assessment, and surveillance.
Creating a common framework
The aim is to reduce variation between institutions and make imaging more comparable, both in clinical practice and in research. The systematic review and joint statement was published in the July 2026 issue of The Lancet Oncology.
It was developed by the Fight Osteosarcoma Through European Research (FOSTER) consortium, the Euro Ewing Consortium, the European Society of Paediatric Radiology, and the European Association of Nuclear Medicine (EANM).
The paper was led by Dr. Laura M.E. Adriaansen, an MD/PhD researcher at the Princess Máxima Center for Pediatric Oncology and the Department of Radiology and Nuclear Medicine at University Medical Center Utrecht in Utrecht, the Netherlands.
A multidisciplinary panel of 36 experts developed the guidance. The literature search identified 2,026 articles for title and abstract screening. Of these, 72 underwent full-text assessment, and 13 were included in the data extraction.
The studies differed widely in diagnoses, chemotherapy regimens, patient populations, and imaging protocols. The panel therefore combined the available evidence with multidisciplinary expertise to formulate 32 consensus-based recommendations according to International Guideline Harmonization Group standards.
Why harmonization matters
Differences between centers can affect which examinations are selected, when they are performed, how treatment response is documented, and how long patients remain under imaging surveillance.
More consistent protocols could make serial examinations easier to compare when patients receive care at different institutions. They could also help researchers combine imaging data from multiple centers, which matters in rare cancers where one institution may not treat enough patients to answer major clinical questions alone.
However, the guideline does not solve every problem. Evidence remained inconclusive regarding the best method for detecting skeletal metastases. Whole-body MRI, bone scintigraphy, and fluorine-18 fluorodeoxyglucose PET/CT are among the approaches used and investigated, but robust prospective comparisons remain limited.
The review also found that no metabolic imaging index or MRI parameter consistently predicted treatment response or survival. Quantitative PET and multiparametric MRI measurements may be promising, but they cannot yet be considered universally validated biomarkers for directing patient management.
Post-treatment surveillance is another major evidence gap. The available data were insufficient to determine the ideal frequency of follow-up imaging, leaving room for variation according to tumor type, age, treatment protocol, and institutional practice.
Potential clinical impact
The guideline’s immediate impact may therefore be greater consistency rather than the replacement of one imaging modality with another.
The recommendations should give radiologists and multidisciplinary sarcoma teams a shared framework for selecting and timing examinations, assessing response, and planning surveillance.
For researchers, harmonized imaging and reporting could make data collected in different countries and institutions easier to pool. International collaboration will be essential to validate response biomarkers, compare metastatic-staging strategies, and determine whether particular surveillance schedules improve patient outcomes.
