Abstract

A recent study, looking at the lifetime risk of developing MPNST (malignant peripheral nerve sheath tumour) in patients with NF1 (neurofibromatosis type 1), estimated the risk to be 8% - 13%. Prior to this, longitudinal studies had shown that patients with NF1 had a risk of 4% - 5% of developing MPNST and cross sectional studies found that only 1-2% of NF1 patients had MPNST. The aim of this study was to estimate the life time risk of MPNST in NF1 patients in southern Scotland, using patient records obtained from the Edinburgh and Glasgow Genetic Units and Scottish Cancer Register (SCR). In the period 1993-2002, 14 patients with NF1 were diagnosed with MPNST in a population of 3.5 million. The lifetime risk of MPNST in the Scottish NF patients was calculated to be 5.9% – 10.3%. This is further evidence that NF1 patients are at greater risk of developing MPNST than was previously estimated and emphasises the importance of educating patients about suspicious symptoms, which may need an urgent medical opinion. Mean age at diagnosis of MPNST was significantly (p<0.05) lower and 5 year survival significantly (p<0.01) less in patients with NF1 than in unaffected individuals. This may be because NF1 patients present later because the tumour is mistaken for a neurofibroma or that MPNST has a more aggressive course in NF1.