title: NF1 plexiform neurofibroma growth rate by volumetric MRI: relationship to age and body weight.
abstract: OBJECTIVE
  To longitudinally analyze changes in plexiform neurofibroma (PN) volume in relation to age and body growth in children and young adults with neurofibromatosis type 1 and inoperable, symptomatic, or progressive PNs, using a sensitive, automated method of volumetric MRI analysis.
  
  
  METHODS
  We included patients 25 years of age and younger with PNs entered in a natural history study or in treatment trials who had volumetric MRI over > or =16 months.
  
  
  RESULTS
  We studied 49 patients (median age 8.3 years) with 61 PNs and a median evaluation period of 34 months (range 18 to 70). The PN growth rates varied among patients, but were constant within patients. Thirty-four patients (69%) experienced > or =20% increase in PN volume during the observation period. PN volume increased more rapidly than body weight over time (p = 0.026). Younger patients had the most rapid PN growth rate.
  
  
  CONCLUSIONS
  Volume increase of plexiform neurofibromas is a realistic and meaningful trial endpoint. In most patients plexiform neurofibroma growth rate exceeded body growth rate. The youngest patients had the fastest plexiform neurofibroma growth rate, and clinical drug development should be directed toward this population. Age stratification for clinical trials for plexiform neurofibromas should be considered.
authors.affiliation: Pediatric Oncology Branch, National Cancer Institute, Bethesda, MD 20892, USA. dombie@mail.nih.gov
authors.forename: E
authors.initials: E
authors.lastname: Dombi
authors.forename: J
authors.initials: J
authors.lastname: Solomon
authors.forename: A J
authors.initials: AJ
authors.lastname: Gillespie
authors.forename: E
authors.initials: E
authors.lastname: Fox
authors.forename: F M
authors.initials: FM
authors.lastname: Balis
authors.forename: N
authors.initials: N
authors.lastname: Patronas
authors.forename: B R
authors.initials: BR
authors.lastname: Korf
authors.forename: D
authors.initials: D
authors.lastname: Babovic-Vuksanovic
authors.forename: R J
authors.initials: RJ
authors.lastname: Packer
authors.forename: J
authors.initials: J
authors.lastname: Belasco
authors.forename: S
authors.initials: S
authors.lastname: Goldman
authors.forename: R
authors.initials: R
authors.lastname: Jakacki
authors.forename: M
authors.initials: M
authors.lastname: Kieran
authors.forename: S M
authors.initials: SM
authors.lastname: Steinberg
authors.forename: B C
authors.initials: BC
authors.lastname: Widemann
mesh_terms: D000375:Aging / Q000473:pathology*; D001835:Body Weight; D002648:Child; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009361:Neoplasm Invasiveness; D018318:Neurofibroma, Plexiform / Q000473:pathology*; D009456:Neurofibromatosis 1 / Q000473:pathology*; D013223:Statistics as Topic