Cardio-Oncology Care: Heart Health For Cancer Survivors
13 Aug 2024 | Murmurs (NHCS)
Heart disease and cancer are top leading causes of death globally.
By Asst Prof Ng Choon Ta, Senior Consultant, Department of Cardiology
The situation is same in Singapore where both heart disease and cancer account for almost 50% of the deaths annually1. While both conditions may seem distinct, emerging evidence highlights the intricate relationship between them. For instance, both heart disease and cancer share similar risk factors such as smoking, ageing, sedentary lifestyle and obesity. Furthermore, cancer treatments such as chemotherapy, targeted therapy, immunotherapy and radiation therapy, can have profound effects on the heart, leading to various cardiac complications which can occur immediately during therapy or even decades after. In fact, cancer survivors living at least five years after diagnosis have up to three times increased cardiovascular risk as compared with age-matched general population without history of cancer2,3. This led to an increasing interest in multidisciplinary field of cardio-oncology. Cardio-oncology focuses on assessing, monitoring and managing cardiovascular toxicities related to cancer treatments with the aim to reduce morbidity and mortality in patients. With the exponential growth in cancer and cardiovascular diseases in Asia, there is an urgent need for cardio-oncology awareness among patients and physicians to ensure comprehensive care for patients battling cancer.
Common Cardiac Complications from Cancer Therapies
While cancer therapy focuses on eradicating the cancerous cells, the heart can sometimes be affected directly or as a bystander. This can cause a spectrum of cardiovascular complications, collectively termed cardiotoxicity, depending on the type of cancer therapy.
Heart failure or cardiomyopathy (disease of the heart muscle)
Chemotherapy, like anthracyclines (a class of drugs) which are used in treating haematological cancers such as lymphomas, can sometimes weaken the heart pumping function over time. This usually occurs at higher cumulative doses. Breast cancer patients on therapies targeting HER2 (a type of protein) may also experience a transient drop in heart function.
In mild cases of reduced heart pumping function, patients may not experience any symptoms. In more severe cases, patients may develop heart failure symptoms such as severe shortness of breath on exertion, and on lying down, legs swelling or lethargy. Sometimes, these symptoms can be nonspecific and may overlap with cancer-related symptoms, making diagnosis challenging. Hence, the presence of heart failure is best assessed with laboratory blood test and biomarkers and confirmed with imaging modalities such as echocardiography or cardiac MRI.
Arrhythmias (irregular heartbeat) such as atrial fibrillation
Patients with cancer are at an increased risk of arrythmias, particularly atrial fibrillation (abnormal heart rhythm characterised by irregular and rapid beating of the heart). Certain types of cancer medications can also cause atrial fibrillation. In cancer patients, there are unique considerations such as risks of bleeding and drug interactions that need be taken into account when considering the treatment of atrial fibrillation.
Patients with atrial fibrillation can sometimes experience palpitations or feel their heart racing. In some instances, patients with ECG smartwatch may get a notification suggesting they have atrial fibrillation despite not having any clinical symptoms. The presence of atrial fibrillation can be confirmed by doing a resting electrocardiogram (which is a surface electrical tracing of the heart) or extended ambulatory ECG monitoring.
Myocardial ischaemia (reduced blood flow to the heart)
Radiation therapy of chest tumours (like those in the mediastinal or left breast) may sometimes affect the heart because of their proximity. In some patients, this can accelerate atherosclerosis (thickening) of the heart vessels, resulting in heart attacks years after radiotherapy. Moreover, some chemotherapy agents may cause vasospasm (narrowing) of the heart vessels, causing chest pain.
Patients with myocardial ischaemia often presents with chest discomfort, which is typically described as heaviness in the chest that is worse with exertion and better with rest. This can sometimes be accompanied by cold sweats or breathlessness.
Hypertension (high blood pressure)
Some cancer therapies such as VEGF (Vascular Endothelial Growth Factor) inhibitors, can cause hypertension or worsen pre-existing hypertension in patients. This may require patients to start or temporarily increase antihypertensive medications.
Myocarditis (inflammation of the heart muscle)
Certain cancer therapies that help the immune system, such as the immune checkpoint inhibitors, can sometimes lead to over-activation of one’s immune system and cause inflammation of the heart muscles, but this is rare.
Strategies or Treatment for Patients on Cancer Therapies:
Risk Assessment and Optimisation:
It is crucial to assess the risk for cardiovascular complications before starting cancer treatment. Patients with pre-existing cardiovascular risk factors or a history of cardiotoxicity should undergo comprehensive cardiac evaluation, including echocardiography and biomarker tests. For prostate cancer patients on hormone therapies, it is important to manage their cardiac risk factors such as high cholesterol, and diabetes4.
Multidisciplinary Approach:
Collaborative care among oncologists, haematologist, cardiologists, and other healthcare providers (nurses, pharmacists, physiotherapists) is essential for managing cancer patients with cardiac complications. This approach ensures comprehensive risk assessment, optimising treatments, and keeping a close monitoring on patients throughout their cancer treatment.
Cardioprotective Strategies:
Several cardioprotective strategies can lower the risk of cardiac complications before and during cancer treatment. These strategies may involve the use of cardioprotective agents like statins with anthracyclines
before starting chemotherapy for lymphomas, the use of medications such as ACE-inhibitors and beta blockers, or regularly monitoring heart function with serial echocardiography.
Lifestyle Modifications:
Encouraging lifestyle changes such as quitting smoking, eating a healthy diet, exercising regularly, and managing weight can help reduce cardiovascular risk for cancer survivors.
Tailored Treatment Approach:
In some cases, adjusting the cancer treatment plan or using alternative therapies with fewer cardiotoxicity side effects may be necessary to balance the cancer control and the protection of the heart.
Survivorship Screening:
For cancer survivors who were exposed to cardiotoxic cancer therapies (such as high-intensity radiation near the heart or high-dose anthracyclines), regular screening may help detect early signs of cardiovascular disease.
The relationship between cancer and heart disease underscores the importance for holistic patient care in cardio-oncology. Cancer survivors have a higher risk of developing cardiovascular complications, necessitating vigilant monitoring and proactive management strategies. With better understanding of the link between cancer and heart disease, doctors and other healthcare professionals can help increase the adherence to cardioprotective measures, and empower their patients with healthier lifestyle changes to bring about better outcomes.
2) Ng CT et al. Advancig Cardio Oncology in Asia. Korean Circ J. 2023 Feb;53(2):69-91. doi: 10.4070/kcj.2022.0255.
3) Kwan ML, Cheng RK, Iribarren C, et al. Risk of heart failure with preserved versus reduced ejection fraction in women with breast cancer. Breast Cancer Res Treat. 2022;193(3):669-675. doi:10.1007/s10549-022-06586-4
4) Ng CT et al. Approaches to Prevent and Manage Cardiovascular Disease in Patients Receiving Therapy for Prostate Cancer. Curr Cardiol Rep 2023 Aug;25(8):889-899.
This article is from Murmurs Issue 47. Click here to read other articles or issues.
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