title: Cancer incidence in patients with schizophrenia and their first-degree relatives - a meta-analysis.
abstract: OBJECTIVE
  Controversy concerning cancer incidence in schizophrenia exists because of heterogeneous study findings.
  
  
  METHODS
  A meta-analysis was performed on standardized incidence ratios (SIR) of cancer in patients with schizophrenia and first-degree relatives and compared with general population samples.
  
  
  RESULTS
  The pooled overall cancer incidence in patients was not significantly increased (SIR = 1.05, CI 0.95-1.15). Lung cancer incidence was slightly increased (SIR = 1.31, CI 1.01-1.71), but was reduced after adjusting for smoking prevalence. The incidence of several cancers unrelated to smoking was reduced in patients. Breast cancer rates were significantly increased in female patients. The pooled overall cancer incidence in siblings (SIR = 0.89, CI 0.84-0.94) and parents (SIR = 0.90, CI 0.88-0.93) was significantly reduced. A meta-regression detected a significant relationship between cancer risk in the general population and relative risk in patients.
  
  
  CONCLUSIONS
  The meta-analysis aided exploration of inconsistent study findings. There is a discrepancy between cancer risk exposure and cancer incidence in schizophrenia consistent with a protective effect.
authors.affiliation: School of Medicine, The University of Queensland, St Lucia, QLD, Australia. s.catts@uq.edu.au
authors.forename: V S
authors.initials: VS
authors.lastname: Catts
authors.forename: S V
authors.initials: SV
authors.lastname: Catts
authors.forename: B I
authors.initials: BI
authors.lastname: O'Toole
authors.forename: A D J
authors.initials: AD
authors.lastname: Frost
mesh_terms: D000368:Aged; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology; D009369:Neoplasms / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000235:genetics*; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology