Cancer survivors have been found to be at a significantly higher risk of cardiovascular disease even after adjustment for known risk factors
Cancer survivors have a greater risk of subsequent cardiovascular disease (CVD) even after adjustment for traditional CVD risk factors, according to the findings of a prospective study by US researchers.
The number of cancer survivors continues to increase due to advances in early detection and treatment. In fact, one study found that in 2019, more than 16.9 million Americans with a history of cancer were alive and this figure is projected to reach more than 22.1 million by 2030. However, the cardiovascular toxicity of cancer treatment has raised awareness of the importance of heart disease in cancer care leading to the new interdisciplinary field of cardio-oncology. This has been driven in part, due to emerging evidence that risk factors associated with cardiovascular disease are also related to an increased incidence of cancer and excess cancer mortality.
It is important therefore, to better understand the burden of CVD among cancer survivors to help improve public health strategies directed towards cardiovascular disease prevention within this patient group.
For the present study, the US researchers undertook a prospective cohort analysis using data from the community-based Atherosclerosis Risk in Communities (ARIC) study, which was designed to investigate the aetiology of atherosclerosis and its clinical sequelae. They set out to examine whether the CVD burden among cancer survivors was independent of traditional CVD risk factors and if this differed between cancers. A subgroup of ARIC patients consented to cancer research and were thus linked to cancer registries.
The researchers examined the incidence of coronary heart disease, heart failure, stroke and composite of these conditions as the outcome of interest and used regression analysis to estimate the association of cancer with these CVD outcomes.
For the analysis they matched every patient, based on sex, age and race who developed cancer with two participants who did not subsequently develop a cancer.
Cancer survivors and cardiovascular disease
A total of 12,421 individuals with a mean age of 54 years (55% female) were included in the analysis, 3,250 of whom developed cancer after a median of 13.6 years. Among women, breast cancer was the most common form of the disease (35%) whereas prostate cancer was the commonest disease in men (40%).
In fully adjusted regression models (i.e., adjusted for known CVD risk factors such as cholesterol levels, diabetes, hypertension, smoking status), cancer survivors had a 37% higher risk of CVD (hazard ratio, HR = 1.37, 95% CI 1.26 – 1.50). This was also significantly higher for heart failure (HR = 1.52, 95% CI 1.38 – 1.68) and stroke (HR = 1.22) but not for coronary heart disease (HR = 1.11, 95% CI 0.97 – 1.28).
When considering individual cancers, survivors of breast cancer had a 32% higher risk of CVD, whereas lung cancer survivors had a much higher increased risk (HR = 2.37).
The authors concluded that cancer survivors are at a higher risk of CVD in comparison to those without cancer and that this excess risk is not explained by traditional CVD risk factors, highlighting the need for CVD prevention strategies in this group.
Florido R et al. Cardiovascular Disease Risk Among Cancer Survivors. The Atherosclerosis Risk In Communities (ARIC) Study J Am Coll Cardiol 2022