title: Cancer in patients with motor neuron disease, multiple sclerosis and Parkinson's disease: record linkage studies.
abstract: OBJECTIVE
  To determine the risk of cancer before and after the diagnosis of motor neuron disease (MND), multiple sclerosis (MS) and Parkinson's disease (PD).
  
  
  METHODS
  Analysis of statistical database of linked statistical abstracts of hospital and mortality data in an area in southern England.
  
  
  RESULTS
  Only people with PD showed a significant difference in the overall incidence of cancer compared with controls (rate ratio (RR) 0.76, 95% CIs 0.70 to 0.82 before PD; RR 0.61, 0.53 to 0.70, after PD). RRs were close to 1 for cancer in patients after MND (0.98, 0.75 to 1.26) and after MS (0.96, 0.83 to 1.09). There were high rate ratios for malignant brain cancer (7.4, 2.4 to 17.5) and Hodgkin's lymphoma (5.3, 1.1 to 15.6) in patients diagnosed with MND after cancer. In people with MS, malignant brain cancer also showed an increased RR both before hospital admission with a diagnosis of MS (3.2, 1.1 to 7.6) and after (2.4, 1.2 to 4.5). In people with PD, several specific cancers showed significantly and substantially reduced RRs for cancer, notably smoking related cancers, including lung cancer (0.5, 0.4 to 0.7, before PD; 0.5, 0.4 to 0.8, after PD) but also cancers that are not strongly smoking related, including colon cancer (0.7, 0.6 to 0.9, before PD; 0.5, 0.4 to 0.8, after PD).
  
  
  CONCLUSIONS
  People with MND, or MS, do not have an altered risk of cancer overall. There may sometimes be misdiagnosis between MND or MS and brain tumours. PD carries a reduced risk of cancer overall, of some smoking related cancers and of some cancers that are not smoking related.
authors.affiliation: Unit of Health-Care Epidemiology, Department of Public Health, University of Oxford, Old Road Campus, Old Road, Oxford, UK.
authors.forename: Alessandro F
authors.initials: AF
authors.lastname: Fois
authors.forename: Clare J
authors.initials: CJ
authors.lastname: Wotton
authors.forename: David
authors.initials: D
authors.lastname: Yeates
authors.forename: Martin R
authors.initials: MR
authors.lastname: Turner
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Goldacre
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000453:epidemiology* / Q000473:pathology; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000473:pathology; D009369:Neoplasms / Q000453:epidemiology* / Q000473:pathology; D010300:Parkinson Disease / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D055815:Young Adult