Cardiovascular Disease Mortality Among Breast Cancer... : Epidemiology (original) (raw)

Cancer

Bradshaw, Patrick T.a; Stevens, Junea,b; Khankari, Nikhilb; Teitelbaum, Susan L.c; Neugut, Alfred I.d; Gammon, Marilie D.b

From the Departments of aNutrition and bEpidemiology, University of North Carolina, Chapel Hill, NC; cDepartment of Preventive Medicine, Mount Sinai School of Medicine, New York, NY; and dDepartments of Medicine and Epidemiology, Columbia University, New York, NY.

Editor’s Note: A commentary accompanying this article appears on page 2.

Submitted 1 October 2014; accepted 11 September 2015.

Supported in part by the National Institutes of Health (UO1CA/ES66572, P30ES10126, CA120780, K12CA120780), Susan G. Komen for the Cure (KG101573), and the American Institute for Cancer Research.

The authors report no conflicts of interest.

Correspondence: Patrick T. Bradshaw, Division of Epidemiology, 101 Haviland Hall, School of Public Health, University of California, Berkeley, Berkeley, CA 94720. E-mail: [email protected].

Abstract

Background:

Cardiovascular disease (CVD) is of increasing concern among breast cancer survivors. However, the burden of this comorbidity in this group relative to the general population, and its temporal pattern, remains unknown.

Methods:

We compared deaths due to CVD in a population-based sample of 1,413 women with incident breast cancer diagnosed in 1996–1997, and 1,411 age-matched women without breast cancer. Date and cause of death through December 31, 2009 were assessed through the national death index and covariate data was gathered through structured interviews and medical record abstraction. Hazard ratios (HR) and 95% confidence intervals were calculated using Cox regression for overall mortality (HR) and CVD-specific death (cause-specific HR). Subdistribution HRs for CVD death were estimated from the Fine-Gray model.

Results:

Risk of death was greater among breast cancer survivors compared with women without breast cancer (HR: 1.8 [1.5, 2.1]). An increase in CVD-related death among breast cancer survivors was evident only 7 years after diagnosis (years 0–7, cause-specific HR: 0.80 [0.53, 1.2], subdistribution HR: 0.59 [0.40, 0.87]); years 7+, cause-specific HR: 1.8 [1.3, 2.5], subdistribution HR: 1.9 [1.4, 2.7]; P interaction: 0.001). An increase in CVD-related mortality was observed among breast cancer survivors receiving chemotherapy.

Conclusions:

Breast cancer survivors are at greater risk for CVD-related mortality compared with women without breast cancer and this increase in risk is manifested approximately 7 years after diagnosis. Efforts should be made to identify risk factors and interventions that can be employed during this brief window to reduce the excess burden of CVD in this vulnerable population.