title: [F-18]-fluorodeoxy-D-glucose-positron emission tomography response is associated with outcome for extremity osteosarcoma in children and young adults.
abstract: BACKGROUND
  Response to neoadjuvant chemotherapy is 1 of the most powerful prognostic factors for extremity osteosarcoma. [F-18]-fluorodeoxy-D-glucose-positron emission tomography (FDG-PET) is a noninvasive imaging modality that is used to predict histopathologic response. To determine the prognostic value of FDG-PET response for progression-free survival (PFS) in osteosarcoma, the authors of this report reviewed the University of Washington Medical Center experience.
  
  
  METHODS
  Forty patients with extremity osteosarcoma were evaluated by FDG-PET. All patients received neoadjuvant and adjuvant chemotherapy. FDG-PET standard uptake values (SUVs) before neoadjuvant chemotherapy (SUV1) and after neoadjuvant chemotherapy (SUV2) were analyzed and correlated with histopathologic response.
  
  
  RESULTS
  The median SUV1 was 6.8 (range, 3.0-24.1), the median SUV2 was 2.3 (range, 1.2-12.8), and the median SUV2 to SUV1 ratio (SUV2:1), was 0.36 (range, 0.12-1.10). A good FDG-PET response was defined as an SUV2<2.5 or an SUV2:1<or=0.5. FDG-PET responses according to SUV2 and SUV2:1 were concordant with histologic response in 58% and 68% of patients, respectively. SUV2 was associated with outcome (4-year PFS, 73% for SUV2<2.5 vs 39% for SUV2>or=2.5; P=.021). Both the initial disease stage and the histologic response were associated with outcome.
  
  
  CONCLUSIONS
  FDG-PET imaging of extremity osteosarcoma was correlated only partially with a histologic response to neoadjuvant chemotherapy. An SUV2<2.5 was associated with improved PFS. Future prospective studies are warranted to determine whether FDG-PET imaging may be used as a predictor of outcome independent of initial disease stage.
authors.affiliation: Department of Pediatrics, Seattle Children's Hospital, and Department of Orthopedics, University of Washington, Seattle, Washington 98105-0371, USA. doug.hawkins@seattlechildrens.org
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Hawkins
authors.forename: Ernest U
authors.initials: EU
authors.lastname: Conrad
authors.forename: James E
authors.initials: JE
authors.lastname: Butrynski
authors.forename: Scott M
authors.initials: SM
authors.lastname: Schuetze
authors.forename: Janet F
authors.initials: JF
authors.lastname: Eary
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D002648:Child; D005121:Extremities; D019788:Fluorodeoxyglucose F18; D006801:Humans; D020360:Neoadjuvant Therapy; D012516:Osteosarcoma / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18