title: Dynamic contrast-enhanced magnetic resonance imaging as a prognostic factor in predicting event-free and overall survival in pediatric patients with osteosarcoma.
abstract: BACKGROUND
  The objective of this study was to prospectively evaluate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as an early imaging indicator of tumor histologic response to preoperative chemotherapy and as a possible prognostic factor for event-free survival (EFS) and overall survival in pediatric patients with newly diagnosed, nonmetastatic osteosarcoma who were treated on a single, multi-institutional phase 2 trial.
  
  
  METHODS
  Three serial DCE-MRI examinations at week 0 (before treatment), week 9, and week 12 (tumor resection) were performed in 69 patients with nonmetastatic osteosarcoma to monitor the response to preoperative chemotherapy. Four DCE-MRI kinetic parameters (the influx volume transfer constant [K(trans) ], the efflux rate constant [k(ep) ], the relative extravascular extracellular space [v(e) ], and the relative vascular plasma space [v(p) ]) and the corresponding differences (ΔK(trans) , Δk(ep) , Δv(e) , and Δv(p) ) of averaged kinetic parameters between the outer and inner halves of tumors were calculated to assess their associations with tumor histologic response, EFS, and overall survival.
  
  
  RESULTS
  The parameters K(trans) , v(e) , v(p) , and k(ep) decreased significantly from week 0 to week 9 and week 12. The parameters K(trans) , v(p) , and Δk(ep) at week 9 were significantly different between responders and nonresponders (P = .046, P = .021, and P = .008, respectively). These 3 parameters were indicative of histologic response. The parameter Δv(e) at week 0 was a significant prognostic factor for both EFS (P = .02) and overall survival (P = .03).
  
  
  CONCLUSIONS
  DCE-MRI was identified as a prognostic factor for EFS and overall survival before treatment on this trial and was indicative of a histologic response to neoadjuvant therapy. Further studies are needed to verify these findings with other treatment regimens and establish the potential role of DCE-MRI in the development of risk-adapted therapy for osteosarcoma.
authors.affiliation: Department of Radiological Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105-3678, USA.
authors.forename: Junyu
authors.initials: J
authors.lastname: Guo
authors.forename: Wilburn E
authors.initials: WE
authors.lastname: Reddick
authors.forename: John O
authors.initials: JO
authors.lastname: Glass
authors.forename: Qing
authors.initials: Q
authors.lastname: Ji
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Billups
authors.forename: Jianrong
authors.initials: J
authors.lastname: Wu
authors.forename: Fredric A
authors.initials: FA
authors.lastname: Hoffer
authors.forename: Sue C
authors.initials: SC
authors.lastname: Kaste
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Jenkins
authors.forename: Ximena C
authors.initials: XC
authors.lastname: Ortega Flores
authors.forename: Juan
authors.initials: J
authors.lastname: Quintana
authors.forename: Milena
authors.initials: M
authors.lastname: Villarroel
authors.forename: Najat C
authors.initials: NC
authors.lastname: Daw
mesh_terms: D000293:Adolescent; D001859:Bone Neoplasms / Q000175:diagnosis* / Q000401:mortality; D002648:Child; D003287:Contrast Media; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D020360:Neoadjuvant Therapy; D012516:Osteosarcoma / Q000175:diagnosis* / Q000401:mortality; D011237:Predictive Value of Tests; D011379:Prognosis
chemical_list: D003287:Contrast Media