Blood, Breast Cancer Survivors Stand Out for Heart Risks Over a Decade Later

Certain cancers remained associated with a wide range of incident cardiovascular disease (CVD) more than a decade down the road, according to a study of U.K. Biobank participants.

Individuals with previous cancer had varying associations with long-term CVD, but the greatest range and magnitude of risk was observed in those with past breast and hematological cancers in particular, relative to propensity-matched non-cancer controls, reported a group led by Zahra Raisi-Estabragh, PhD, of Queen Mary University of London's William Harvey Research Institute.

Encompassing lymphoma, leukemia, and myeloma, hematological cancer was associated with increased risk of all types of incident CVD over 12 years of follow-up. What's more, cardiac MRI revealed larger chamber volumes, lower ejection fractions, and poorer left ventricular (LV) strain suggestive of adverse cardiac remodeling in this group.

Meanwhile, breast cancer was associated with select CVD risks (e.g., excess pericarditis, non-ischemic cardiomyopathy, heart failure death, hypertensive disease death), and survivors showed a tendency toward a lower LV ejection fraction and a lower LV global function index on imaging, the investigators reported in Heart.

"Importantly, we demonstrate that past cancer confers an increased risk of cardiovascular events, independent of traditional vascular risk factors and that this risk may extend several years beyond the initial cancer diagnosis. Thus, our results support consideration of cancer-specific exposures in cardiovascular risk stratification and lower thresholds for treatment of modifiable risk factors in this patient group," Raisi-Estabragh and colleagues said.

Beyond blood and breast cancers, lung cancer, prostate cancer, and uterine cancer were also tied to some CVD events to varying degrees.

"The pattern of CVDs varies by cancer site, likely reflecting specific characteristics of the cancer and its therapies. CMR [cardiac MRI] measures of LV and LA [left atrial] structure and function provide preclinical indicators of cardiovascular health in this context," the authors suggested.

Patients with cancer often have various demographic and clinical risk factors that place them at higher cardiovascular risk. According to CDC estimates, cancer survivorship ages the heart on average by 8.5 years for men and 6.5 years for women. Excess cardiovascular risk can be attributed in part to shared vascular risk factors between cancer and heart disease, cardiotoxicity of cancer therapies, and biological processes unique to the cancer itself.

The exact contributions of cancer vs cancer therapies remain unclear and are not addressed by the present study.

Nevertheless, the authors have opened the door to some precision in the follow-up care of cancer survivors, according to an accompanying editorial by Jose Banchs, MD, of University of Colorado School of Medicine, Aurora, and Tara Lech, PharmD, of Beth Israel Lahey Health in Westwood, Massachusetts.

"With this knowledge, we could start refining follow-up strategies that, given the particular incidents of each cancer, would include an emphasis on cardiac functional imaging, ECG evaluation and close attention to venous thrombotic symptoms for those survivors of breast, lung and colorectal malignancies," Banchs and Lech wrote. "This is a step further from the most current guidelines."

The U.K. Biobank includes over half a million people who had been recruited in 2006-2010. For the present analysis, Raisi-Estabragh and co-authors identified 18,714 participants with past cancer (67% women, median age 62 years, 97% white), of whom 1,354 provided cardiac MRI data.

Participants with cancer generally had a high burden of vascular risk factors and prevalent CVD.

Altogether, cancer survivors had a 30.7% incidence of any CVD -- compared with 24.5% for controls -- over 11.8 years of prospective follow-up. The highest CVD rates were in those with lung (49.5%), hematological (48.4%), and prostate cancers (40.6%) -- people who also happened to be more likely to be smokers.

Raisi-Estabragh's group acknowledged that the study's reliance on health records leaves room for errors resulting from miscoding of incident outcomes. Additionally, lung and uterine cancer survivors were represented by small samples, making relevant analyses underpowered in the study.

"Building on these findings to design follow-up studies that consider cancer-specific exposures and guided cardiovascular risk stratification strategies would be possible," Banchs and Lech said.

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