title: Statin use after diagnosis of breast cancer and survival: a population-based cohort study.
abstract: BACKGROUND
  Preclinical studies have shown that statins, particularly simvastatin, can prevent growth in breast cancer cell lines and animal models. We investigated whether statins used after breast cancer diagnosis reduced the risk of breast cancer-specific, or all-cause, mortality in a large cohort of breast cancer patients.
  
  
  METHODS
  A cohort of 17,880 breast cancer patients, newly diagnosed between 1998 and 2009, was identified from English cancer registries (from the National Cancer Data Repository). This cohort was linked to the UK Clinical Practice Research Datalink, providing prescription records, and to the Office of National Statistics mortality data (up to 2013), identifying 3694 deaths, including 1469 deaths attributable to breast cancer. Unadjusted and adjusted hazard ratios (HRs) for breast cancer-specific, and all-cause, mortality in statin users after breast cancer diagnosis were calculated using time-dependent Cox regression models. Sensitivity analyses were conducted using multiple imputation methods, propensity score methods and a case-control approach.
  
  
  RESULTS
  There was some evidence that statin use after a diagnosis of breast cancer had reduced mortality due to breast cancer and all causes (fully adjusted HR = 0.84 [95% confidence interval = 0.68-1.04] and 0.84 [0.72-0.97], respectively). These associations were more marked for simvastatin 0.79 (0.63-1.00) and 0.81 (0.70-0.95), respectively.
  
  
  CONCLUSIONS
  In this large population-based breast cancer cohort, there was some evidence of reduced mortality in statin users after breast cancer diagnosis. However, these associations were weak in magnitude and were attenuated in some sensitivity analyses.
authors.affiliation: From the aCancer Epidemiology and Health Services Research Group, Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom; bSchool of Pharmacy, Queen's University Belfast, Northern Ireland, United Kingdom; and cCentre of Excellence for Public Health (NI), Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors.forename: Chris R
authors.initials: CR
authors.lastname: Cardwell
authors.forename: Blanaid M
authors.initials: BM
authors.lastname: Hicks
authors.forename: Carmel
authors.initials: C
authors.lastname: Hughes
authors.forename: Liam J
authors.initials: LJ
authors.lastname: Murray
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality*; D002318:Cardiovascular Diseases / Q000401:mortality / Q000517:prevention & control*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries; D019821:Simvastatin / Q000627:therapeutic use*; D015996:Survival Rate
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D019821:Simvastatin