Hemangiosarcoma (HSA) is an aggressive and often deadly cancer in dogs, known for affecting the blood vessels and spreading rapidly. One of the most common locations for HSA in dogs is the heart, particularly the right atrium and the surrounding tissues, including the pericardium (the sac surrounding the heart). Heart-based hemangiosarcoma is a serious condition that requires early diagnosis and treatment to improve the dog’s quality of life. This article will focus on understanding the symptoms, diagnosis, and general care for dogs affected by this common heart tumor.

What is Hemangiosarcoma?

Hemangiosarcoma is a malignant cancer that originates in the endothelial cells that line blood vessels. While this cancer can develop in various organs, including the liver, spleen, and skin, its presence in the heart is particularly dangerous due to its impact on cardiovascular function. When HSA forms in the heart, it typically leads to complications such as pericardial effusion (fluid accumulation in the pericardium) and impaired heart function.

Common Locations of Hemangiosarcoma in the Heart:

• Right atrium: The most frequent site for cardiac hemangiosarcoma.
• Pericardium: Tumors can also affect the outer sac of the heart, leading to fluid buildup.

The aggressive nature of HSA means that, by the time it is diagnosed, it has often spread (metastasized) to other parts of the body, including the lungs, liver, or spleen.

Symptoms of Hemangiosarcoma in Dogs

Hemangiosarcoma in the heart can be difficult to detect in its early stages, as symptoms may not be obvious until the tumor has grown significantly or caused a rupture. However, there are certain clinical signs that can alert pet owners to potential problems:

Common Symptoms of Cardiac Hemangiosarcoma:

1. Lethargy and Weakness: Dogs with hemangiosarcoma often display reduced energy levels and may collapse due to poor blood circulation or heart failure.
2. Difficulty Breathing (Dyspnea): Fluid accumulation around the heart can make it harder for dogs to breathe normally.
3. Coughing: A persistent, unexplained cough can be a sign of fluid buildup or pressure from the tumor on the lungs.
4. Pale Gums: Anemia caused by internal bleeding may result in pale gums, which can be an early sign of a heart or blood vessel problem.
5. Abdominal Swelling: If the tumor causes bleeding into the abdominal cavity, this may result in visible swelling.
6. Fainting or Collapse: Some dogs may faint or collapse suddenly due to reduced blood flow from the heart or internal hemorrhaging.
7. Exercise Intolerance: Dogs may be unable to exercise or walk as much as they used to because of reduced heart function.

These symptoms often worsen over time, as the tumor grows and compromises the heart’s ability to function properly.

Diagnosis of Canine Hemangiosarcoma

Early detection of hemangiosarcoma in the heart is critical, but diagnosing the condition can be challenging due to its nonspecific symptoms. Veterinarians use several diagnostic tools to confirm the presence of hemangiosarcoma and assess the extent of the disease.

1. Physical Examination

A veterinarian may notice signs like muffled heart sounds, pale gums, or signs of fluid accumulation in the chest, which can prompt further investigation.

2. Echocardiogram (Ultrasound of the Heart)

An echocardiogram is one of the most important diagnostic tools for identifying heart tumors. It allows the veterinarian to visualize the heart in real-time, detect the presence of a mass, and assess the amount of fluid in the pericardium. Echocardiography can also help determine if the tumor is affecting heart function.

3. X-rays

Chest X-rays can reveal fluid buildup around the heart and may show if the cancer has spread to the lungs. X-rays are useful for determining the overall health of the chest cavity.

4. CT Scans and MRIs

In more complex cases, advanced imaging techniques like CT scans or MRIs may be used to get a clearer picture of the tumor and its impact on surrounding tissues.

5. Pericardiocentesis

In cases where there is fluid around the heart, a procedure called pericardiocentesis may be performed. This involves inserting a needle into the pericardium to remove the fluid for analysis. While this procedure relieves pressure on the heart, it also provides valuable information about the nature of the fluid and helps confirm a diagnosis of hemangiosarcoma.

6. Blood Tests

Although blood tests cannot definitively diagnose hemangiosarcoma, they may show signs of anemia, abnormal clotting, or organ dysfunction, which can prompt further testing.

Treatment of Hemangiosarcoma in Dogs

The treatment of hemangiosarcoma in dogs focuses on both managing the symptoms and extending the dog’s lifespan. Unfortunately, due to the aggressive nature of the disease, the prognosis is often poor, and treatment is aimed primarily at palliative care.

1. Surgery

In cases where the tumor can be surgically removed, surgery may be recommended. However, complete removal of heart-based hemangiosarcoma is challenging, and the cancer often recurs. Surgery can also be used to remove fluid buildup around the heart to relieve symptoms.

2. Chemotherapy

Chemotherapy is often used in conjunction with surgery or as a standalone treatment to slow the progression of the disease. Common chemotherapy drugs like doxorubicin are used to target cancer cells, though the response to treatment varies from dog to dog.

3. Palliative Care

For dogs where surgery or chemotherapy is not an option, palliative care focuses on improving the dog’s quality of life. This can include medications to manage pain, heart medications to reduce fluid accumulation, and procedures like pericardiocentesis to drain excess fluid and relieve pressure on the heart.

4. Holistic Therapies

Some pet owners may explore holistic approaches, such as nutritional support, herbal supplements, or acupuncture, to improve their dog’s comfort during treatment.

Prognosis for Dogs with Hemangiosarcoma

The prognosis for dogs diagnosed with cardiac hemangiosarcoma is generally poor, with most dogs surviving only a few months after diagnosis, even with treatment. Without treatment, the average survival time is just a few weeks. However, with early intervention and aggressive treatment, some dogs may live several months, and in rare cases, longer.

Hemangiosarcoma is a challenging and aggressive cancer in dogs, particularly when it affects the heart. Early recognition of symptoms, such as difficulty breathing, lethargy, and fainting, is key to diagnosing this condition. While treatment options are limited and focused on managing symptoms, timely intervention can improve the dog’s quality of life and extend survival. Pet owners should work closely with their veterinarians to explore all available treatment options, including surgery, chemotherapy, and palliative care.