Cancer Epidemiol Biomarkers Prev

BackgroundThe role of comorbidities in survival of breast cancer patients has not been well studied, particularly in non-white populations.MethodsWe 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 hazards ratios (HR) and 95% confidence intervals (CI) for overall and breast cancer-specific mortality associated with previous cancer, diabetes, high blood pressure (HBP), and myocardial infarction (MI).ResultsRisk 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 MI (HR=1.94, 95% CI=1.27\u20132.97). 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 radiation nor chemotherapy (HR=2.11, 95% CI=1.32\u20133.36); no increased risk was observed among those who received both treatments (HR=1.13, 95% CI= 0.70\u20131.84) (P interaction= 0.03). A similar pattern was found for MI by radiation and chemotherapy (P interaction=0.09).ConclusionThese results may inform future treatment guidelines for breast cancer patients with a history of diabetes or MI.ImpactGiven the growing number of breast cancer survivors worldwide, we need to better understand how comorbidities may adversely affect treatment decisions and ultimately outcome.20142015-08-03T00:00:00Z1U58 DP000807-01/DP/NCCDPHP CDC HHS/United StatesHHSN261201000140C/PHS HHS/United StatesHHSN26120100034C/PHS HHS/United StatesHHSN26120100035C/PHS HHS/United StatesK05 CA136967/CA/NCI NIH HHS/United StatesN01-HD-3-3175/HD/NICHD NIH HHS/United StatesN01CN25403/CN/NCI NIH HHS/United StatesR01 CA077398/CA/NCI NIH HHS/United StatesR01 CA129059/CA/NCI NIH HHS/United StatesR01 CA54281/CA/NCI NIH HHS/United StatesR01 CA63446/CA/NCI NIH HHS/United StatesR01 CA77305/CA/NCI NIH HHS/United StatesR01 CA77398/CA/NCI NIH HHS/United StatesR37CA54281/CA/NCI NIH HHS/United StatesUM1 CA164973/CA/NCI NIH HHS/United States25425578PMC4523272712