title: Is genetic background important in lung cancer survival?
abstract: BACKGROUND
  In lung cancer, a patient's survival is poor with a wide variation in survival within the stage of disease. The aim of this study was to investigate the familial concordance in lung cancer survival by means of analyses of pairs with different degrees of familial relationships.
  
  
  METHODS
  Our population-based Swedish family database included three million families and over 58,100 lung cancer patients. We modelled the proband (parent, sibling, spouse) survival utilizing a multivariate proportional hazard (Cox) model adjusting for possible confounders of survival. Subsequently, the survival in proband's relative (child, sibling, spouse) was analysed with a Cox model.
  
  
  RESULTS
  By use of Cox modelling with 5 years follow-up, we noted a decreased hazard ratio for death in children with good parental survival (Hazard Ratio [HR] = 0.71, 95% CI = 0.51 to 0.99), compared to those with poor parental survival. Also for siblings, a very strong protective effect was seen (HR = 0.14, 95% CI = 0.030 to 0.65). Finally, in spouses no correlation in survival was found.
  
  
  CONCLUSIONS
  Our findings suggest that genetic factors are important in lung cancer survival. In a clinical setting, information on prognosis in a relative may be vital in foreseeing the survival in an individual newly diagnosed with lung cancer. Future molecular studies enhancing the understanding of the underlying mechanisms and pathways are needed.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden. Linda.Lindstrom@ki.se
authors.forename: Linda S
authors.initials: LS
authors.lastname: Lindström
authors.forename: Per
authors.initials: P
authors.lastname: Hall
authors.forename: Mikael
authors.initials: M
authors.lastname: Hartman
authors.forename: Fredrik
authors.initials: F
authors.lastname: Wiklund
authors.forename: Kamila
authors.initials: K
authors.lastname: Czene
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012727:Sex Characteristics; D035781:Siblings; D012923:Social Class; D018454:Spouses; D016019:Survival Analysis; D013548:Sweden