title: Characteristics and outcomes of patients with Ewing sarcoma over 40 years of age at diagnosis.
abstract: BACKGROUND
  The peak incidence of Ewing sarcoma (EWS) is in adolescence, with little known about patients who are ≥40 years at diagnosis. We describe the clinical characteristics and survival of this rare group.
  
  
  METHODS
  This retrospective cohort study utilized the Surveillance Epidemiology and End Results database. 2780 patients were identified; including 383 patients diagnosed ≥40 years. Patient characteristics between age groups were compared using chi-squared tests. Survival from diagnosis to death was estimated via Kaplan-Meier methods, compared with log-rank tests, and modeled using multivariable Cox methods. A competing risks analysis was performed to evaluate death due to cancer.
  
  
  RESULTS
  Patients ≥40 years of age were more likely to have extra-skeletal tumors (66.1% vs. 31.7%; p < 0.001), axial tumors (64.0% vs. 57.2%; p = 0.01), and metastatic disease at diagnosis (35.5% vs. 30.0%; p = 0.04) compared to younger patients. Five-year survival for those age ≥40 and age <40 were 40.6% and 54.3%, respectively (p < 0.0001). A Cox multivariable model controlling for differences between groups confirmed inferior survival for older patients (hazard ratio for death of 2.04; 95% CI 1.63-2.54; p < 0.0001); though treatment data were unavailable and not controlled for in the model. A competing risks analysis confirmed increased risk of cancer-related death in older patients.
  
  
  CONCLUSIONS
  Patients ≥40 years at diagnosis with EWS are more likely to have extra-skeletal tumors, metastatic disease, and axial primary tumors suggesting a difference in tumor biology. Independent of differences in these characteristics, older patients also have a lower survival rate.
authors.affiliation: Department of Pediatrics, UCSF School of Medicine, San Francisco, CA 94143-0106, USA. KarskiE@peds.ucsf.edu
authors.forename: Erin E
authors.initials: EE
authors.lastname: Karski
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Matthay
authors.forename: John M
authors.initials: JM
authors.lastname: Neuhaus
authors.forename: Robert E
authors.initials: RE
authors.lastname: Goldsby
authors.forename: Steven G
authors.initials: SG
authors.lastname: Dubois
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018426:SEER Program; D012512:Sarcoma, Ewing / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology*; D015996:Survival Rate; D014481:United States / Q000453:epidemiology; D055815:Young Adult