Not all tumors are cancerous (malignant). Some cancers may be benign (non-cancerous). Most tumors of the heart are non-cancerous (benign). Cancer is the second most common cause of death in the United States after heart disease. Some organs are more likely to be affected with cancer, like the lungs, colon, rectum, prostate (men) and breast (women). Other organs, like the heart, are less likely to develop cancer.
It is important to differentiate between primary and secondary (metastatic) cancer. A primary malignant tumor is where the cancer arises from the cells of the organ where it is located, in this case the heart. However, sometimes cancerous cells can break away from another organ and lodge in the heart where it then forms a malignant (cancerous) tumor. These cancers are referred to as secondary or metastatic cancer.
Read more on heart tumors.
What is cardiac sarcoma?
Cardiac sarcoma is cancer that arises from the heart and surrouding lining (pericardium). It is the most common heart cancer that develops from the heart tissue (primary cancer). Overall a cardiac sarcoma is a rare type of cancer and is mostly discovered during an autopsy. The signs and symptoms of cardiac sarcomas are non-specific and therefore easily missed.
Furthermore the rarity of this type of cancer also means that it is not often considered as a possible cause of symptoms. There are no specific causes of cardiac sarcomas that have been identified. Even pericardial mesothelioma (around the heart), the third most common type of cardiac sarcoma, is not associated with asbestos exposure as is the case with pleural mesothelioma (around the lungs).
Types of Cardiac Sarcomas
There are several subtypes of cardiac sarcomas. This includes:
- Fibrosarcoma and malignant fibrous histiocytoma
- Malignant schwannoma
- Metastatic cardiac sarcoma
The list above is of cardiac sarcomas in decreasing order of frequency among adults. The three most common types of cardiac sarcomas – angiosarcoma, rhabdomyosarcoma and mesothelioma – have been discussed in detail below.
Angiosarcomas are the most common of the cardiac sarcomas. These cancers are usually symptomatic and can lead to death within a short period of time. It mainly occurs in the right atrium, usually arising from the inner layer of the heart where it fills the chamber and destroys neighboring structures like the vena cava and heart valve.
Rhabdomyosarcoma is the second most common type of cardiac sarcoma. This type of heart cancer may occur in all age groups and is the most common form of cardiac sarcoma in children. Unlike angiosarcoma, it can occur anywhere in the heart and often affects the heart muscle (myocardium).
These types of tumors arise from the lining around the heart known as the pericadium but usually do not extend into the heart muscle (myocardium). It may extend to the pleura (lining around the lungs), diaphragm and even the peritoneum (lining of the abdomen).
Signs and Symptoms
The signs and symptoms of a cardiac sarcoma can vary depending on the type and location of the tumor. There is no typical presentation. Fatigue, chest pain and difficulty breathing are some of the symptoms that may occur. However, these symptoms are non-specific and more likely to be due to other more common cardiac and/or respiratory conditions.
The most common type, an angiosarcoma, usually involves the right atrium where it may occupy most of the chamber. This affects the return of blood to the heart. This cause symptoms like:
- Leg swelling
- Abdominal distension
- Neck vein distension
When the heart muscle is infiltrated as is the case with a rhabdomyosarcoma then the contraction and relaxation of the heart is affected. This may cause symptoms like:
- Abnormally slow or rapid heart rate
- Irregular heartbeat (arrhythmia)
If the pericardium (lining around the heart) is involved then there may be accumulation of fluid around the heart. This is known as a cardiac tamponade and may present with symptoms like:
- Diminished cardiac sounds
- Friction rub
It is important to note that these symptoms among the different cardiac tumors are not as specific for each type. Cancer is not usually restricted to just a specific area or layer of the heart and will often infiltrate all layers within a short period of time. Other signs and symptoms of cardiac sarcomas include:
- Hemoptysis – bloody vomiting
- Night sweats
- Weight loss
In addition, emboli may occur where small portions of the tumors may break away from the heart and travel through the bloodstream to other parts of the body. These emboli can block the blood flow to different organs, such as to the brain which may result in a stroke.
Diagnosis of Cardiac Sarcomas
There are various imaging techniques to diagnose a cardiac tumor. Early diagnosis is uncommon as many people only seek medical attention once symptoms arise. Usually at this point the prognosis is poor. The following investigations may be used to diagnose cardiac sarcomas:
- Computed tomography (CT scan)
- Chest x-ray
- Magnetic resonance imaging (MRI)
Electrocardiography (ECG) will reveal abnormalities in the electrical activity of the heart which is common in cardiac sarcomas. However, this is non-specific and cannot be used to diagnose a cardiac sarcoma.
Treatment of Cardiac Sarcomas
These tumors are not usually cured. Once there are symptoms evident, the tumor usually has already spread (metastasis). The prognosis is therefore poor at this point. However, surgical removal of the tumor helps to improve the quality of life by relieving some of the symptoms and prolonging survival. The tumor may be excised (“cut out”) partially or completely. Radiation and chemotherapy after the surgery is not always beneficial.
How deadly is cardiac sarcoma?
All cancers are serious, especially when it is not diagnosed early. This is often the case with heart cancer. In addition, with the risk of emboli due to the tumor being located in the heart, the cancer cells are more likely to spread to other parts of the body. The median survival for all types of cardiac sarcomas is approximately 6 months. Survival tends to be longer with tumors on the left side of the heart.