Hypertension, diabetes, and dyslipidemia are commonly cited risk factors for cardiovascular disease (CVD). This list is not exhaustive, however. This article establishes a need to test and monitor patients receiving cancer treatments for CVD.

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Cancer has been shown to be strongly related to CVD. According to research published by BMC Cancer, survivors of cancer are more likely to die of CVD-related causes than of cancer-related ones.

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Quantifying the issue

More than 80% of patients with cancer survive long-term. Cancer treatments and complications of the disease, however, can increase the risk of CVD.

Johns Hopkins researchers analysed the risk of CVD in a prospective community-based study. It included 12,414 ARIC (atherosclerosis risk in communities) study participants (mean age: 54 years; 55% women). The researchers calculated incident CVD outcomes, including heart failure, coronary artery disease, stroke, and a composite of these conditions.

Overall, 25% of the study population exhibited incident cancers during a median follow-up of 13.6 years. After adjusting for other CVD risk factors, cancer survivors were at 52% higher risk of CVD and 22% higher risk of stroke. They did not exhibit higher rates of coronary heart disease.

According to an article published by the Journal of the American College of Cardiology, the investigators also found that breast, lung, colorectal, and hematologic/lymphatic cancers were related to CVD risk. Prostate cancer was not.

“Major advances in cancer treatment mean that patients are living longer and longer,” said Elizabeth Selvin, PhD, MPH, senior author of the study in the Johns Hopkins article. “This means we now need to pay attention to other chronic diseases, especially heart disease, in cancer survivors.”

“Cancer survivors are a high-risk population and should be prioritised for interventions that lower the chance of heart disease later in life.”

— Elizabeth Selvin, PhD, MPH

In the prospective study published in BMC Cancer, Taiwanese researchers assessed the risk of cancer in 552,485 cancer patients (mean age: 60.6 years; 47.7% women) during a median follow-up period of 4.1 years.

They found that there were 32,634 cases of fatal and non-fatal CVD, and when compared with a non-cancer population, the fully adjusted heart rate (HR) of CVD was 1.28. CVD risk was highest during the first year after a cancer diagnosis, with an HR of 2.31. That risk dropped after the first year.

The researchers also found that the risk of CVD was highest in patients with lung cancer and lowest in those with thyroid and breast cancer. 

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Role of cancer treatment

Cancer treatment can result in cardiotoxicity by many mechanisms, including oxidative stress (eg, mitochondrial functional impairment), microtubule dysfunction, myocardial apoptosis, and disruption of myocardial immune homeostasis.

“Since the heart has a weak antioxidant capacity, high concentrations of ROS [reactive oxygen species] predispose cardiomyocytes to mitochondrial damage and lipid peroxidation, affecting myocardial function,” wrote the authors of a review published in Frontiers in Cardiovascular Medicine.

Drugs that cause cardiotoxicity via oxidative stress include anthracyclines and anti-epidermal growth factor receptor 2 (ErbB2) drugs. These agents mediate mitochondrial damage in cardiomyocytes, resulting in irreversible myocardial damage.

Because they result in immune regulation, immune-checkpoint inhibitors—which are used in solid and hematologic cancer—could be less detrimental to the heart, a thesis that has been supported by research. Nevertheless, immunotherapy may lead to cardiac arrest, fulminant myocarditis, and shock, according to the Frontiers in Cardiovascular Medicine authors.

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Managing CVD risk

1. Before initiating cancer treatment—especially those that could be cardiotoxic—it’s important to establish a baseline.
2. Patients should be screened for risk of CVD and diabetes, receive an echo, and have other biomarkers checked. In patients with pre-existing CVD who are about to initiate cancer treatment, a more detailed assessment for CVD comorbidities is required.
3. Patients with tumours who are at high risk for CVD should be closely monitored for signs and symptoms of CVD. Antitumor therapies with clear cardiovascular risks should be avoided in these patients, according to the Frontiers in Cardiovascular Medicine article.

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Diagnosing CVD in patients with cancer

Cancer patients should have their blood pressure regularly monitored, along with their ECG. Close attention should be paid to acute ST-segment elevation indicating myocardial infarction and arrhythmias.

Echocardiography is the best way to monitor left ventricular ejection fraction and other measures of cardiac function in patients with cancer. Echo is also used to diagnose valvular abnormalities. Three-dimensional echo is preferred because it visualises the endocardial boundary.

Cardiac magnetic resonance imaging is considered the gold standard for assessing left ventricular volume and ejection fraction. An endomyocardial biopsy can help determine the extent of myocardial injury, although this procedure is highly invasive.

Arterial and venous ultrasound of the bilateral lower extremities is the best way to diagnose venous thromboembolism. Computed tomography pulmonary angiography is the gold standard for diagnosing a pulmonary embolism (PE) and can be used to confirm PE following a diagnosis of deep venous thromboembolism, according to the Frontiers in Cardiovascular Medicine research.

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This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.