Hemangiosarcoma in Dogs: Causes, Symptoms, and Treatment

What is Hemangiosarcoma Cancer in Dogs?

Hemangiosarcoma (HSA) in dogs is a malignant, aggressive cancer in dogs that starts within the cells lining blood vessels (endothelial cells). According to the Flint Animal Cancer Center, hemangiosarcoma in dogs is a fairly common cancer, accounting for about 5% of total cancer cases. 

As a cancer of the cells lining blood vessels, hemangiosarcoma in dogs can occur anywhere in the body. However, there are several sites that are most commonly affected by this cancer: skin, spleen, heart, and liver. There are two main hemangiosarcoma tumor types:

• Visceral Hemangiosarcoma in Dogs. Visceral hemangiosarcoma develops internally, with the most common organ being the spleen (the abdominal organ that fights against infections and removes dead red blood cells from the circulatory system). Being a malignant tumor, hemangiosarcoma is very aggressive and spreads quickly. Hemangiosarcoma of the spleen is sometimes referred to as spleen cancer, splenic HSA, or splenic hemangiosarcoma.    
• Cutaneous Hemangiosarcoma in Dogs. Hemangiosarcoma of the skin surface is a common tumor of the endothelial cells lining the skin blood vessels. This form of hemangiosarcoma is locally aggressive and has a high rate of spreading to other organs.   

In general, as a tumor type, hemangiosarcoma frequently affects dogs and is very rare in humans and other animals like cats and rodents.    

Do Dogs Suffer When They Have Hemangiosarcoma? 

In the early stage of the disease, dogs with hemangiosarcoma usually don’t suffer, even though the cancer is very aggressive. The disease often doesn’t cause any symptoms in its early stages. 

Serious symptoms tend to start in the late stages of the disease. In the end stages, hemangiosarcoma in dogs can cause significant discomfort. 

What Causes Hemangiosarcoma in Dogs?

As with many other cancers, it is hard to point out the exact cause of HSA. In most cases, a combination of several risk factors contributes to cancer development. These risk factors are listed below:

• Sun Exposure. It is believed that cutaneous hemangiosarcomas are caused by excessive sun exposure. Thus, short-haired and light-skinned dogs seem to be most affected by this type of cancer. Hemangiosarcoma of the skin also mostly occurs on parts of the body with the least amount of hair, like the abdomen and nose of short-haired dogs. 
• Genetics. The evidence of heritable factors contributing to hemangiosarcoma is supported by certain breeds being predisposed to cancer. The incidence of hemangiosarcoma is higher in medium- to large-breed dogs, such as German Shepherds, Dobermans, Golden Retrievers, Labrador Retrievers, English Setters, Portuguese Water Dogs, and Boxers. 
• Age. A dog’s age also plays a role in the development of hemangiosarcoma. This cancer is most common in middle-aged and older dogs. However, canine hemangiosarcoma may also occur in puppies. 

What are the Symptoms of Hemangiosarcoma in Dogs? 

The signs and symptoms of hemangiosarcoma in dogs largely depend on the stage and site of the tumor. 

Cutaneous HSA, also known as dermal hemangiosarcoma in dogs, can be distinguished by a mass of red or black growth on the skin of a dog. The mass may become ulcerated and bleed.

Hemangiosarcoma of the heart will produce clinical signs related to changes in normal cardiac function. One such clinical sign is an arrhythmia (irregular heartbeat), which occurs when electrical signals in the heart that control the heart beat stop working as they should. Another sign is pericardial effusion, which is fluid build-up in the pericardial sac that surrounds and protects the heart. The symptoms of cardiac tumors are striking and specific. 

Rupture of a splenic tumor can result in abdominal distension, pale gums, blood loss, internal bleeding, and increased heart and respiratory rates.

Non-specific signs of hemangiosarcoma in dogs include:

• Nosebleeds
• Slow wound healing rate
• Exercise intolerance
• Difficulty breathing 
• Abdominal swelling
• Pale gums and mucous membranes 

If your dog develops any of the symptoms above, schedule an appointment with your vet for a definitive diagnosis.

Diagnosing Hemangiosarcoma Cancer in Dogs

Dermal hemangiosarcoma in dogs is relatively easy to diagnose with fine-needle aspiration. During fine-needle aspiration, your vet will insert a long, thin needle into the tumor to collect a sample of your dog’s tumor cells and examine those cells under a microscope. 

Visceral hemangiosarcoma in dogs is much more complicated to diagnose. In most cases, the diagnosis of visceral hemangiosarcoma happens after the tumor ruptures.  A ruptured splenic mass needs immediate surgical intervention to stop the bleeding. After the surgery, chest radiographs are recommended to see if the tumor has spread. 

If your dog’s tumor has not yet ruptured and your dog doesn’t need emergency surgery, your veterinarian will perform a series of diagnostic tests to confirm if your dog has hemangiosarcoma. The tests include blood tests, urine tests, x-rays of the chest, white blood cell count, and a biopsy of the tumor. Generally speaking, a biopsy is a golden standard for cancer diagnosis. The procedure involves removing a small section of a tumor, then using a microscope to examine the tumor sample for cancerous properties, such as abnormal-looking cells and a high rate of cell replication.

After analyzing the initial diagnostic test results, the veterinarian may suggest a referral to a veterinary oncologist for additional diagnostic testing or more advanced treatments.

How do You Treat Hemangiosarcoma Cancer in Dogs? 

The best ways to treat HSA in dogs are surgery, chemotherapy, and radiation therapy. Cancer in dogs treatment is a complex topic. Usually, the best treatment for HSA will depend on the location of the primary tumor, the aggressiveness of the tumor, and the cost of treatment. 

Surgical Treatment. Surgical resection is a good option for tumors that show no evidence of metastasis (spreading). It is most commonly performed on skin hemangiosarcoma in the subcutaneous tissue (tissue layer just beneath the outermost layer of skin). The addition of chemotherapy after surgery is sometimes recommended to get rid of all remaining cancer cells; this is called adjuvant chemotherapy. Surgical removal of the primary tumor doesn’t guarantee a full cure, but it usually extends the survival time and remains the primary method of treatment for hemangiosarcoma in dogs.

Chemotherapy and Radiotherapy. Chemotherapy and radiotherapy are recommended for patients in which the tumor has metastasized. Chemotherapy can extend your dog’s life but will not itself cure cancer. The drug doxorubicin is the most commonly used chemotherapy drug to treat HSA in dogs. The average survival time with chemotherapy after surgery is about six months. Palliative radiation therapy can be used to slow tumor growth. 

Supportive Therapy. Blood transfusions and fluid therapy are critical aspects of supportive therapy, especially if a dog needs to be stabilized before the emergency surgery. The exact extent and type of supportive therapy is something the vet will decide according to the specifics of a dog’s cancer diagnosis and health status. 

In addition to the standard treatment that your vet will prescribe for your dog, you also have a role to play in your dog’s cancer treatment: ensuring a good quality of life for your dog. Cancer treatment can be a very difficult time for a dog, so you have to try your best to make it manageable. 

One way you can help your dog is by supplementing her medical treatment with holistic therapy options, such as acupuncture, physical therapy, herbs, and CBD oil. Always consult with your vet before using the holistic options listed below to ensure that they don’t interfere with your dog’s cancer treatment regimen. 

Cannabidiol (CBD) Products. Recent studies have demonstrated the positive effects of CBD for dogs with cancer. The CBD’s anti-inflammatory effects of CBD can help manage cancer symptoms and chemotherapy side effects. We recommend the Honest Paws CBD Products, which are made with full-spectrum hemp-derived CBD. 

Yunnan Baiyao. The Chinese supplement Yunnan Baiyao is used in human medicine to manage bleeding. Its use in veterinary medicine is relatively new and there are not many clinical studies reviewing its effects. However, based on anecdotal information, the Yunnan Baiyao supplement may be beneficial for dogs with hemangiosarcoma.    

Honest Paws

• Specifically formulated to relieve occasional joint stiffness and discomfort in your dog
• Made with organic, full-spectrum hemp oil and other all-natural ingredients
• Supports connective tissue

Check Price

What can I do to Prevent Hemangiosarcoma Cancer in Dogs? 

The question of how to prevent cancer in dogs is tricky and often without an exact answer. Although you cannot totally prevent your dog from getting hemangiosarcoma, you can lower your dog’s risk by following these tips: 

Limiting sun exposure. Dogs with light-colored fur, short hair, or thin-haired coats are most susceptible to dermal hemangiosarcoma. Don’t leave these dogs outside in the sun for too long! Perhaps even consider some doggie sunscreen.

Maintaining a healthy weight. Being overweight predisposes your dog to many chronic diseases, including cancer. Dogs that are overweight should be put on a healthy weight loss regimen that includes a nutritionally rich and balanced diet and regular exercise and physical activity. 

Living a healthy lifestyle. Feed your dog a high-quality diet, and make sure your dog always has fresh drinking water. Maintaining a healthy lifestyle for your dog can go a long way in helping your dog have a long and healthy life. A healthy lifestyle can be especially important if you have breeds, such as German Shepherd Dogs or Boxers, that is genetically at risk of developing hemangiosarcoma.

Regular check-ups.  Early cancer detection can improve your dog’s chances of having a good prognosis. A thorough physical examination by your veterinarian once a year can identify clinical signs of diseases even before you realize that your dog has a particular health condition.

Get good pet insurance. One more way you can help your dog fight against hemangiosarcoma is by signing up for a good pet health insurance policy. The OneVet Pet Insurance Plan is the best deal you can get for you and your dog. For only $19.99 a month, you get:

• Unlimited access to a licensed veterinarian through a mobile app or your browser
• $3,000/year emergency fund to pay your veterinary bills
• Cover for preexisting conditions (no matter your pet’s age) for up to 6 pets. 

What is the Life Expectancy of a Dog With Hemangiosarcoma? 

The life expectancy of a dog with hemangiosarcoma varies according to where the cancer is located. For example, dogs with dermal hemangiosarcoma have an average survival of 780 days. Dogs with visceral hemangiosarcoma have shorter survival times, even with treatment. For splenic hemangiosarcoma, a dog may survive 1-2 months if treated with only surgery. 

Hemangiosarcoma has a very poor prognosis because the diagnosis is usually made late in the disease process. There is often very little warning of cancer in the early stages. 

On the other hand, the long-term prognosis may be more favorable in the case of early detection. 

What are the End Stages of Hemangiosarcoma in Dogs? 

The end stages of hemangiosarcoma are very difficult for both dogs and their families. Some of the signs and symptoms you can expect in the late stages of the disease include:

• Distended abdomen
• Difficulty breathing
• Lack of coordination (ataxia)
• Arrhythmia
• Blood in dog stool
• Sudden loss of consciousness or fainting
• Weak pulse 
• Sudden death. 

In cases in which a dog is struggling and its quality of life is poor, it is advisable to consider euthanasia. Euthanasia is a tough choice and you should ask the vet all the questions about euthanasia that you might have before making a final decision.