While cancer treatments are known to affect cardiovascular health, the disease itself can also directly or indirectly lead to heart problems. Cancer can influence the heart and circulatory system independently of treatment side effects. This article explores the various ways cancer can affect the heart.
Direct Tumor Effects
Cancer can physically affect the heart through the presence of tumors within or near cardiac structures. Primary heart tumors, which originate in the heart tissue, are rare. These tumors can form in any part of the heart, potentially obstructing blood flow or interfering with heart function.
More commonly, cancer spreads to the heart from other parts of the body, a process known as metastasis. Cancers of the lung, breast, melanoma, lymphoma, and leukemia frequently metastasize to the heart, often affecting the pericardium, the sac surrounding the heart. These metastatic tumors can invade the heart directly, spread through the lymphatic system, or travel via the bloodstream.
Tumors located in adjacent areas, such as the mediastinum (the space in the chest between the lungs), can also compress the heart or major blood vessels. Such compression can lead to serious conditions like pericardial effusion, where fluid builds up around the heart, or cardiac tamponade, a life-threatening condition where the heart is squeezed by this fluid, impairing its ability to pump blood. Direct tumor involvement can also cause arrhythmias, which are irregular heartbeats, or obstruct blood flow within the heart chambers or valves.
Indirect Paraneoplastic Effects
Certain cancers can influence the heart through indirect means, known as paraneoplastic syndromes. These occur when cancer cells produce substances, such as hormones, cytokines, or antibodies, that travel through the bloodstream and cause effects in distant organs, including the heart, even when the tumor is not physically present there. These substances can trigger a range of cardiac issues.
One specific example is carcinoid syndrome, which arises from certain neuroendocrine tumors that release vasoactive substances. These substances can lead to the thickening and damage of heart valves, particularly on the right side of the heart, resulting in valvular dysfunction. Other paraneoplastic syndromes might cause inflammation of the heart muscle, known as myositis, or affect the electrical conduction system of the heart, leading to arrhythmias.
Systemic Body Responses
Cancer can also induce broader physiological changes throughout the body that place significant strain on the cardiovascular system. Chronic inflammation, a common feature of many cancers, contributes to systemic inflammatory responses that can damage the inner lining of blood vessels. This endothelial dysfunction can accelerate the development of atherosclerosis, a condition where plaque builds up in the arteries, narrowing them and restricting blood flow.
Cancer often creates a state of hypercoagulability, meaning the blood has an increased tendency to clot. This heightened clotting risk can lead to serious cardiovascular events, including deep vein thrombosis (DVT) in the legs and pulmonary embolism (PE) in the lungs, both of which can strain the right side of the heart. Cancer-related anemia, caused by the disease itself or its treatments, forces the heart to work harder to deliver sufficient oxygen to the body’s tissues, increasing cardiac workload and potentially leading to heart failure.
Cancer cachexia, a wasting syndrome characterized by significant weight loss and muscle atrophy, can also impact the heart. This systemic wasting can include the loss of heart muscle mass, which compromises the heart’s pumping efficiency and overall function. These widespread systemic changes, driven by the cancer’s presence, collectively contribute to a heightened risk of various cardiac complications, underscoring the pervasive nature of the disease’s influence on the body.
Identifying and Managing Cardiac Concerns
Recognizing cardiac symptoms in individuals with cancer is important for early detection and management. Symptoms that warrant attention include shortness of breath, chest pain or pressure, swelling in the legs or abdomen, heart palpitations, and unexplained fatigue. These signs could indicate developing cardiac complications and should prompt discussion with healthcare providers.
Open communication with the medical team about any new or worsening symptoms is a proactive step in managing cardiovascular health during cancer. Diagnostic approaches may involve an electrocardiogram (ECG) to assess the heart’s electrical activity, an echocardiogram to visualize heart structure and function, and various blood tests to check for markers of cardiac strain or inflammation. These tests help determine the nature and extent of any heart involvement.
General management strategies focus on addressing the underlying issues and alleviating symptoms. This might include managing anemia to reduce cardiac workload, using medications to control arrhythmias, or implementing anticoagulation therapy to prevent blood clots. Lifestyle adjustments, such as maintaining physical activity as tolerated and a balanced diet, can also support overall cardiovascular well-being. Early identification and appropriate management are important for mitigating potential cardiac complications in individuals affected by cancer.