title: Prognostic factors and patterns of relapse in ewing sarcoma patients treated with chemotherapy and r0 resection.
abstract: OBJECTIVE
  To identify prognostic factors and patterns of relapse for patients with Ewing sarcoma who underwent chemotherapy and R0 resection without radiation therapy (RT).
  
  
  METHODS
  We reviewed the medical records of patients who underwent surgical resection at our institution between 2000 and 2013 for an initial diagnosis of Ewing sarcoma. The associations of demographic and clinical factors with local control (LC) and patient outcome were determined by Cox regression. Time to events was measured from the time of surgery. Survival curves were estimated by the Kaplan-Meier method and compared by the log-rank test.
  
  
  RESULTS
  A total of 66 patients (median age 19 years, range 4-55 years) met the study criteria. The median follow-up was 5.6 years for living patients. In 43 patients (65%) for whom imaging studies were available, the median tumor volume reduction was 73%, and at least partial response by Response Evaluation Criteria in Solid Tumors was achieved in 17 patients (40%). At 5 years, LC was 78%, progression-free survival (PFS) was 59%, and overall survival (OS) was 65%. Poor histologic response (necrosis ≤95%) was an independent predictor of LC (hazard ratio [HR] 6.8, P=.004), PFS (HR 5.2, P=.008), and OS (HR 5.0, P=.008). Metastasis on presentation was also an independent predictor of LC (HR 6.3, P=.011), PFS (HR 6.8, P=.002), and OS (HR 6.7, P=.002). Radiologic partial response was a predictor of PFS (HR 0.26, P=.012), and postchemotherapy tumor volume was associated with OS (HR 1.06, P=.015). All deaths were preceded by distant relapse. Of the 8 initial local-only relapses, 5 (63%) were soon followed by distant relapse. Predictors of poor postrecurrence survival were time to recurrence <1 year (HR 11.5, P=.002) and simultaneous local and distant relapse (HR 16.8, P=.001).
  
  
  CONCLUSIONS
  Histologic and radiologic response to chemotherapy were independent predictors of outcome. Additional study is needed to determine the role of adjuvant radiation therapy for patients who have poor histologic response after R0 resection.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Hubert Y
authors.initials: HY
authors.lastname: Pan
authors.affiliation: Department of Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Ajaykumar
authors.initials: A
authors.lastname: Morani
authors.affiliation: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Wei-Lien
authors.initials: WL
authors.lastname: Wang
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Hess
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Arnold C
authors.initials: AC
authors.lastname: Paulino
authors.affiliation: Department of Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Ludwig
authors.affiliation: Department of Orthopedic Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Patrick P
authors.initials: PP
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Najat C
authors.initials: NC
authors.lastname: Daw
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: amahajan@mdanderson.org.
authors.forename: Anita
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality; D011379:Prognosis; D012044:Regression Analysis; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D055815:Young Adult