While cancer does not directly cause a heart attack like traditional cardiovascular disease, it significantly increases the risk. The relationship between cancer and heart health is multifaceted, involving both the effects of cancer treatments and the biological impacts of the disease itself. This article explores how cancer and its therapies can influence cardiovascular well-being, potentially leading to serious cardiac events.
How Cancer Treatments Impact the Heart
Cancer treatments can have unintended consequences for the cardiovascular system. Certain chemotherapy drugs are known for their cardiotoxic effects. Anthracyclines, such as doxorubicin, directly damage heart muscle cells (cardiomyocytes) by increasing reactive oxygen species, leading to oxidative stress and DNA damage. This can result in conditions like dilated cardiomyopathy and heart failure, increasing the risk of acute coronary events. Platinum-based drugs also contribute to cardiotoxicity.
Radiation therapy directed at the chest can also significantly affect the heart. It can damage the lining of blood vessels, promoting inflammation and fibrosis in the heart muscle, valves, and arteries. This damage accelerates coronary artery disease, where plaque builds up in the heart’s arteries, increasing heart attack risk. Radiation can also cause pericarditis, an inflammation of the sac surrounding the heart, and valvular heart disease, where heart valves thicken or stiffen, impairing blood flow.
Newer cancer treatments, including targeted therapies and immunotherapies, also carry cardiac side effects. Targeted therapies can induce hypertension or arrhythmias. Immunotherapies, particularly immune checkpoint inhibitors, can cause myocarditis, an inflammation of the heart muscle, by prompting immune cells to attack healthy heart tissue. Though rare, this myocarditis can be severe and potentially fatal. These injuries increase the risk for acute cardiac events.
How Cancer Itself Affects Heart Health
Beyond treatment effects, cancer itself can influence cardiovascular risk. Cancer often induces chronic systemic inflammation. This persistent inflammation drives atherosclerosis, the hardening and narrowing of arteries due to plaque buildup. Pro-inflammatory cytokines like interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha contribute to this process, increasing heart attack risk.
Certain cancers also lead to a hypercoagulable state, an increased tendency for blood clot formation. Cancer cells can release procoagulant substances, such as tissue factor, which activate the blood clotting cascade. These clots can form in deep veins or travel to the lungs, and in rarer instances, they can contribute to a heart attack if they block coronary arteries.
In some rare cases, cancer can trigger paraneoplastic syndromes, where the tumor produces substances affecting distant organs, including the heart. These syndromes can lead to various cardiac issues, such as arrhythmias or cardiomyopathy. For example, some tumors might secrete hormones that impact cardiac function, or the immune system might produce antibodies that mistakenly attack heart tissue.
Advanced cancer can also lead to cachexia, a severe wasting syndrome characterized by significant loss of muscle mass and physical decline. This systemic debilitation can strain the cardiovascular system. Cardiac muscle atrophy and dysfunction have been observed in patients with cachexia, which can impair the heart’s ability to pump blood effectively, increasing the risk of cardiac events.
Recognizing and Managing Cardiac Risks
Given the potential for cardiovascular complications in cancer patients, proactive recognition and management of cardiac risks are important. Before initiating cancer treatment, a baseline cardiovascular assessment is often conducted. This may include an electrocardiogram (ECG) to check heart rhythm and an echocardiogram to evaluate heart structure and function, establishing a starting point for monitoring.
Regular cardiac monitoring continues during and after cancer treatment, especially for individuals receiving cardiotoxic therapies or those at higher risk. This surveillance can involve repeated echocardiograms to track changes in left ventricular function, and blood tests for cardiac biomarkers like troponin and natriuretic peptides, which indicate heart muscle damage or strain. The frequency of these tests depends on the specific treatment and individual risk factors.
Managing traditional cardiovascular risk factors, such as high blood pressure, high cholesterol, and diabetes, is also important for cancer patients. These conditions can independently contribute to heart problems and may be exacerbated by cancer or its treatments. Adopting healthy lifestyle modifications, including a balanced diet, regular physical activity, and stress management techniques, can further support cardiovascular health.
Patients are encouraged to communicate any new or worsening symptoms, such as chest pain, shortness of breath, or swelling, to their oncology and cardiology teams. This open communication facilitates early detection and intervention for potential cardiac issues. The field of cardio-oncology specializes in addressing the unique cardiovascular needs of cancer patients, providing integrated care that balances cancer treatment effectiveness with heart health preservation.