title: Utility of bone marrow aspiration and biopsy in initial staging of Ewing sarcoma.
abstract: BACKGROUND
  The current standard of care for initial staging of pediatric Ewing sarcoma (EWS) patients is to obtain a bilateral bone marrow aspiration and biopsy (BMAB). The incidence of bone marrow (BM) disease in patients deemed non-metastatic by conventional and metabolic imaging and the concordance of BM positivity with other clinical characteristics are not well established.
  
  
  METHODS
  This study is a multi-institutional retrospective review of newly diagnosed EWS patients less than 40 years of age with initial staging that included imaging and BMAB.
  
  
  RESULTS
  A total of 116 patients were eligible with 85 patients considered non-metastatic and 31 considered metastatic by imaging. None of the 85 patients with non-metastatic disease were BMAB positive (0%; 95% CI: 0-4.2%); 13 of the 31 patients with metastases were BMAB positive (41.9%; 95% CI: 24.5-60.9%). Primary tumor size was significantly higher in patients with metastases (P = 0.017). Bone metastasis by imaging had high correlation with BMAB positivity (P = 0.0002). In addition, the number of bony metastatic sites was significantly higher in patients with a positive BMAB as compared to those with a negative BMAB (median 3.5 and 0.0, respectively; P < 0.001).
  
  
  CONCLUSIONS
  BMAB may not be required for initial staging of pediatric and young adult EWS patients deemed non-metastatic by imaging. In patients with metastatic disease, there is a high correlation of BM involvement with multiple bone metastases.
authors.affiliation: Department of Pediatrics, Division of Hematology/Oncology/BMT University of Arizona, Tucson, Arizona.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Kopp
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Hu
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rozo
authors.forename: Andrea
authors.initials: A
authors.lastname: White-Collins
authors.forename: Winston W
authors.initials: WW
authors.lastname: Huh
authors.forename: Angela
authors.initials: A
authors.lastname: Yarborough
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Herzog
authors.forename: Pooja
authors.initials: P
authors.lastname: Hingorani
mesh_terms: D000293:Adolescent; D000328:Adult; D001707:Biopsy, Needle / Q000706:statistics & numerical data*; D001853:Bone Marrow / Q000473:pathology*; D001859:Bone Neoplasms / Q000556:secondary* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D003952:Diagnostic Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000473:pathology* / Q000601:surgery; D055815:Young Adult
keywords: Ewing sarcoma; bone marrow aspiration; bone marrow biopsy; bone scan; pediatrics; staging