title: Malignant peripheral nerve sheath tumours in neurofibromatosis 1.
abstract: BACKGROUND
  Cross sectional studies have shown that 1-2% of patients with neurofibromatosis 1 (NF1) develop malignant peripheral nerve sheath tumours (MPNST). However, no population based longitudinal studies have assessed lifetime risk.
  
  
  METHODS
  NF1 patients with MPNST were ascertained from two sources for our north west England population of 4.1 million in the 13 year period 1984-1996: the North West Regional NF1 Register and review of notes of patients with MPNST in the North West Regional Cancer Registry.
  
  
  RESULTS
  Twenty-one NF1 patients developed MPNST, equivalent to an annual incidence of 1.6 per 1000 and a lifetime risk of 8-13%. There were 37 patients with sporadic MPNST. The median age at diagnosis of MPNST in NF1 patients was 26 years, compared to 62 years in patients with sporadic MPNST (p<0.001). In Kaplan-Meier analyses, the five year survival from diagnosis was 21% for NF1 patients with MPNST, compared to 42% for sporadic cases of MPNST (p=0.09). One NF1 patient developed two separate MPNST in the radiation field of a previous optic glioma.
  
  
  CONCLUSIONS
  The lifetime risk of MPNST in NF1 is much higher than previously estimated and warrants careful surveillance and a low threshold for investigation.
authors: University Department of Medical Genetics, St Mary's Hospital, Manchester M13 0JH, UK. Gevans@central.cmht.nwest.nhs.uk
authors: D G R
authors: DG
authors: Evans
authors: M E
authors: ME
authors: Baser
authors: J
authors: J
authors: McGaughran
authors: S
authors: S
authors: Sharif
authors: E
authors: E
authors: Howard
authors: A
authors: A
authors: Moran
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009456:Neurofibromatosis 1 / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D018570:Risk Assessment; D015996:Survival Rate