Current Practices and Variations in the Use of FDG-PET and Bone Marrow Biopsy in Ewing Sarcoma Diagnosis: A Survey of Provider Recommendations

INTRODUCTION: Ewing sarcoma (ES) is the second most common malignant bone and soft tissue tumor in children, adolescents, and young adults. Current consensus guidelines, consistent with Children's Oncology Group practice, support the universal use of full-body fluorodeoxyglucose positron emission tomography (FDG-PET) and recommend reserving bone marrow aspiration and biopsy for cases in which FDG-PET raises concern for marrow involvement, leaving final decisions to the treating physician. Although bone marrow metastasis is defined by morphologic evidence on biopsy rather than imaging alone, the extent to which these recommendations have influenced real-world practice is unknown.

METHODS: A cross-sectional electronic survey of pediatric hematology-oncology and transplant attending physicians, advanced practice providers, and fellows was conducted to gather data on current practices regarding FDG-PET use and the decision to include bone marrow evaluation.

RESULTS: A total of 392 providers completed this survey. Nearly all general oncologists (n=172) and solid tumor specialists (n=156) reported obtaining an FDG-PET for every patient presenting with ES, compared with all other hematology/oncology subspecialty providers (P=0.002). Providers who always obtain FDG-PET for newly diagnosed ES patients had a lower median year in practice (9 [3 to 17]) than those who do not (19 [8 to 21]) (P=0.018). However, more than half of providers reported obtaining a BM biopsy on every patient, independent of FDG-PET results. Based on a guideline-informed system, solid tumor oncologists demonstrated somewhat greater alignment with practice-based approaches compared with general oncologists (P=0.013).

DISCUSSION: This study highlights the variation in the diagnostic evaluation of ES. Increased education and incorporation of practice-based guidelines into upfront clinical trials may help reduce practice variability.