Reassessing Bone Marrow Aspirate and Trephine Biopsies in Staging for Paediatric and Young Adult Patients With Ewing Sarcoma and Rhabdomyosarcoma

ABSTRACT

Ewing sarcoma (ES) and rhabdomyosarcoma (RMS) are aggressive malignancies in children and adolescents where metastases impact prognosis. 18F‐fluoro‐2‐deoxy‐

‐glucose positron emission tomography/computed tomography (FDG‐PET/CT) and bone marrow aspirate and trephine biopsies (BMAT) are used to identify disease involvement. Literature suggests that BMAT may not be required for staging when FDG‐PET/CT is performed in ES. However, BMAT continues to be performed. This retrospective audit re‐reviewed staging practices in the ES cohort to confirm the applicability of existing evidence and extended the analysis to include patients with RMS, where there is comparatively less evidence. This review provides insight into whether reduction in investigations is feasible in the broader sarcoma population. A total of 240 patients with histologically confirmed ES (128) or RMS (112) diagnosed between 2006 and 2020 were reviewed. A total of 133 patients met inclusion criteria. The sensitivity of FDG‐PET/CT for bone marrow involvement for all patients was 92%, and the negative predictive value of FDG‐PET/CT was 99%. The sensitivity and negative predictive value were each 100% in the ES group and 88% and 98%, respectively, in the RMS group. This suggests that FDG‐PET/CT is adequate in identifying patients who do not have bone marrow involvement. Thus, we propose if marrow disease is not identified on FDG‐PET/CT, a BMAT could be omitted from the patient's workup.