title: Diabetes and other comorbidities in breast cancer survival by race/ethnicity: the California Breast Cancer Survivorship Consortium (CBCSC).
abstract: BACKGROUND
  The role of comorbidities in survival of patients with breast cancer has not been well studied, particularly in non-white populations.
  
  
  METHODS
  We investigated the association of specific comorbidities with mortality in a multiethnic cohort of 8,952 breast cancer cases within the California Breast Cancer Survivorship Consortium (CBCSC), which pooled questionnaire and cancer registry data from five California-based studies. In total, 2,187 deaths (1,122 from breast cancer) were observed through December 31, 2010. Using multivariable Cox proportional hazards regression, we estimated HRs and 95% confidence intervals (CI) for overall and breast cancer-specific mortality associated with previous cancer, diabetes, high blood pressure (HBP), and myocardial infarction.
  
  
  RESULTS
  Risk of breast cancer-specific mortality increased among breast cancer cases with a history of diabetes (HR, 1.48; 95% CI, 1.18-1.87) or myocardial infarction (HR, 1.94; 95% CI, 1.27-2.97). Risk patterns were similar across race/ethnicity (non-Latina white, Latina, African American, and Asian American), body size, menopausal status, and stage at diagnosis. In subgroup analyses, risk of breast cancer-specific mortality was significantly elevated among cases with diabetes who received neither radiotherapy nor chemotherapy (HR, 2.11; 95% CI, 1.32-3.36); no increased risk was observed among those who received both treatments (HR, 1.13; 95% CI, 0.70-1.84; P(interaction) = 0.03). A similar pattern was found for myocardial infarction by radiotherapy and chemotherapy (P(interaction) = 0.09).
  
  
  CONCLUSIONS
  These results may inform future treatment guidelines for patients with breast cancer with a history of diabetes or myocardial infarction.
  
  
  CONCLUSIONS
  Given the growing number of breast cancer survivors worldwide, we need to better understand how comorbidities may adversely affect treatment decisions and ultimately outcome.
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California. anna.wu@med.usc.edu.
authors.forename: Anna H
authors.initials: AH
authors.lastname: Wu
authors.affiliation: Stanford University School of Medicine, Stanford, California.
authors.forename: Allison W
authors.initials: AW
authors.lastname: Kurian
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Kwan
authors.affiliation: Stanford University School of Medicine, Stanford, California. Cancer Prevention Institute of California, Fremont, California.
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.affiliation: City of Hope, Duarte, California.
authors.forename: Yani
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Stanford University School of Medicine, Stanford, California. Cancer Prevention Institute of California, Fremont, California.
authors.forename: Theresa H M
authors.initials: TH
authors.lastname: Keegan
authors.affiliation: Stanford University School of Medicine, Stanford, California. Cancer Prevention Institute of California, Fremont, California.
authors.forename: Scarlett Lin
authors.initials: SL
authors.lastname: Gomez
authors.affiliation: Stanford University School of Medicine, Stanford, California. Cancer Prevention Institute of California, Fremont, California.
authors.forename: Iona
authors.initials: I
authors.lastname: Cheng
authors.affiliation: Stanford University School of Medicine, Stanford, California. Cancer Prevention Institute of California, Fremont, California.
authors.forename: Salma
authors.initials: S
authors.lastname: Shariff-Marco
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Bette J
authors.initials: BJ
authors.lastname: Caan
authors.affiliation: Division of Research, Kaiser Permanente Northern California, Oakland, California.
authors.forename: Valerie S
authors.initials: VS
authors.lastname: Lee
authors.affiliation: City of Hope, Duarte, California.
authors.forename: Jane
authors.initials: J
authors.lastname: Sullivan-Halley
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Chiu-Chen
authors.initials: CC
authors.lastname: Tseng
authors.affiliation: City of Hope, Duarte, California.
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Richard
authors.initials: R
authors.lastname: Sposto
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Vigen
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000208:ethnology* / Q000401:mortality*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000208:ethnology* / Q000401:mortality*; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016016:Proportional Hazards Models; D015996:Survival Rate