title: Family history of colorectal cancer is not associated with colorectal cancer survival regardless of microsatellite instability status.
abstract: BACKGROUND
  Individuals with a family history of colorectal cancer in first-degree relatives have an elevated risk of developing colorectal cancer themselves, particularly colorectal cancer exhibiting high microsatellite instability (MSI-high). Given that MSI-high colorectal cancer is associated with a favorable prognosis, it is plausible that having a family history of colorectal cancer could, in turn, be favorably associated with colorectal cancer survival.
  
  
  METHODS
  This study comprised N = 4,284 incident colorectal cancer cases enrolled in the Colon Cancer Family Registry via population-based cancer registries. Using Cox proportional hazards regression, we evaluated the association between family history and both overall and disease-specific survival, accounting for MSI status and tumor site via stratified analyses and statistical adjustment.
  
  
  RESULTS
  There was no evidence of association between family history and overall [hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.79-1.08] or disease-specific survival (HR, 1.03; 95% CI, 0.85-1.24) for all cases combined, after adjustment for MSI status or tumor site. Only for rectal cancer cases was colorectal cancer family history modestly associated with more favorable overall survival (HR, 0.75; 95% CI, 0.56-0.99).
  
  
  CONCLUSIONS
  Although individuals with a family history of colorectal cancer were more likely to have MSI-high tumors than those with nonfamilial disease, this did not translate to a survival benefit.
  
  
  CONCLUSIONS
  Overall, there is no evidence that family history of colorectal cancer is associated with colorectal cancer survival; however, specific mechanisms underlying family history may have prognostic impact and merit further study.
authors.affiliation: Epidemiology Department, University of Washington; Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; aiphipps@u.washington.edu.
authors.forename: Amanda I
authors.initials: AI
authors.lastname: Phipps
authors.affiliation: Division of Gastroenterology, University of Colorado School of Medicine, Denver, Colorado;
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Ahnen
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, Georgia;
authors.forename: Peter T
authors.initials: PT
authors.lastname: Campbell
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia;
authors.forename: Aung Ko
authors.initials: AK
authors.lastname: Win
authors.affiliation: Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia;
authors.forename: Mark A
authors.initials: MA
authors.lastname: Jenkins
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Scottsdale, Arizona;
authors.forename: Noralane M
authors.initials: NM
authors.lastname: Lindor
authors.affiliation: Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada; and.
authors.forename: Robert
authors.initials: R
authors.lastname: Gryfe
authors.affiliation: Epidemiology Department, University of Washington; Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington; Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors.forename: John D
authors.initials: JD
authors.lastname: Potter
authors.affiliation: Epidemiology Department, University of Washington; Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington;
authors.forename: Polly A
authors.initials: PA
authors.lastname: Newcomb
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries