Cardiovascular Risk Factors, Cardiac Events, and Survival in Patients With Breast Cancer Enrolled in SWOG Clinical Trials

Key Points

  • Each additional cardiovascular risk factor was associated with poorer overall survival.
  • Each additional risk factor was associated with borderline significant poorer progression-free and cancer-specific survival.   

In a study reported in the Journal of Clinical Oncology, Hershman et al found that each additional baseline cardiovascular disease risk factor was associated with increased risk for cardiac events and death among Medicare patients who had been enrolled in SWOG trials in breast cancer.

Study Details   

The study involved women enrolled in SWOG breast cancer trials from 1999 to 2011. Baseline diabetes, hypertension, hypercholesterolemia, and coronary artery disease were identified by linking trial records to Medicare claims. The primary outcome was overall survival. Overall, 1,460 participants aged > 66 years from five trials were identified, with 842 being eligible for survival analysis.

Risk Factors and Survival

At baseline, median age was 70 years. Median follow-up was 6 years. Hypertension (73%) and hypercholesterolemia (57%) were the most common cardiovascular risk factors, with 87% of patients having one or more risk factor. No association was observed between any individual risk factor and overall survival, except for a significant survival benefit for hypercholesterolemia (hazard ratio [HR] = 0.73, P = .01). With each additional risk factor present at baseline, there were significant or marginally significant increases in risk for all-cause mortality (HR = 1.23, P = .002), poorer progression-free survival (HR = 1.12, P = .05), and poorer cancer-free survival (HR = 1.15, P = .07). Among 736 patients eligible for analysis of cardiac events, a strong linear association was observed for number of baseline risk factors and risk of a cardiac event (HR per risk factor = 1.41, P < .001).

The investigators concluded, “Among participants in clinical trials, each additional baseline [cardiovascular disease risk factor] was associated with an increased risk of cardiac events and death. Efforts to improve control of modifiable [cardiovascular disease risk factors] are needed, especially among those with multiple risk factors.”

The study was supported by the National Cancer Institute, Conquer Cancer Foundation, Breast Cancer Research Foundation, and Susan G. Komen Research Foundation.

Dawn L. Hershman, MD, of Columbia University Medical Center, is the corresponding author for the Journal of Clinical Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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