title: Relative mortality rates from incident chronic diseases among breast cancer survivors--a 14 year follow-up of five-year survivors diagnosed in Denmark between 1994 and 2007.
abstract: BACKGROUND
  It remains unknown whether incident chronic diseases are more often fatal among breast cancer survivors than among women free of breast cancer.
  
  
  METHODS
  We conducted a nationwide matched cohort study of all Danish breast cancer patients diagnosed between 1994 and 2007, who survived for five years. We compared their long-term mortality with five times as many women from the general population without breast cancer, matched on age. We used time-varying methods to compute mortality rate ratios (MRRs) for incident diseases included in the Charlson Comorbidity Index (CCI).
  
  
  RESULTS
  One third of five-year breast cancer survivors developed incident diseases during 14 years of follow-up, with about the same incidence as women without breast cancer. Mortality associated with any incident disease was similar among breast cancer survivors (MRR = 7.1, 95% confidence interval (CI): 6.7, 7.4) and comparison women (MRR = 7.5, 95% CI: 7.3, 7.7). Among breast cancer patients, relative mortality associated with incident diseases was higher among patients treated with chemotherapy (MRR = 10, 95% CI: 8.7, 12) and radiotherapy (MRR = 9.8, 95% CI: 8.8, 11) than among patients who received surgery (MRR = 7.0, 95% CI: 6.7, 7.4) or hormonal therapy (MRR = 6.3, 95% CI: 5.8, 6.9).
  
  
  CONCLUSIONS
  There were no marked differences in mortality of diseases among breast cancer survivors and women from the general population. Among breast cancer patients, new diseases were more often fatal in patients treated with chemotherapy and radiotherapy. Five-year breast cancer survivors have similar risk of dying from new chronic medical conditions as women from the general population without breast cancer.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Denmark. Electronic address: ao@clin.au.dk.
authors.forename: Anne Gulbech
authors.initials: AG
authors.lastname: Ording
authors.affiliation: Institute for Translational Epidemiology, Mount Sinai School of Medicine, New York, NY, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Boffetta
authors.affiliation: Breast Clinic, Aalborg Hospital, Aalborg University Hospital, Denmark.
authors.forename: Jens Peter
authors.initials: JP
authors.lastname: Garne
authors.affiliation: Department of Oncology, Uppsala University Hospital, Sweden.
authors.forename: Petra Mariann Witt
authors.initials: PM
authors.lastname: Nyström
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Denmark.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Cronin-Fenton
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Denmark.
authors.forename: Trine
authors.initials: T
authors.lastname: Frøslev
authors.affiliation: Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Silliman
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Denmark.
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Lash
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality*; D002908:Chronic Disease / Q000401:mortality*; D015331:Cohort Studies; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009026:Mortality; D012307:Risk Factors; D017741:Survivors
keywords: Breast neoplasm; Comorbidity; Epidemiology; Mortality; Multimorbidity; Survival