Understanding Hemangiosarcoma in Dogs: Causes, Symptoms, and Support

At Kali’s Wish Cancer Foundation, we know how devastating a cancer diagnosis can be for a beloved pet. Hemangiosarcoma is one of the most aggressive and heartbreaking cancers affecting dogs, and many families turn to us for pet cancer support and guidance. This article will help you understand hemangiosarcoma—its causes, symptoms, treatments, and ways you can find help if your dog is affected.

What is Hemangiosarcoma?

Hemangiosarcoma is a malignant cancer that originates in the cells lining blood vessels. Because blood vessels run throughout the body, this cancer can develop in many organs. The most common sites include:

• Spleen (splenic hemangiosarcoma)

• Heart (cardiac hemangiosarcoma)

• Liver

• Skin and soft tissues

This cancer is extremely aggressive and often spreads before symptoms appear, making early diagnosis difficult.

Breeds at Higher Risk

While any dog can develop hemangiosarcoma, some breeds are more predisposed due to hereditary factors. These include:

• Golden Retrievers

• German Shepherds

• Labrador Retrievers

• Boxers

• Portuguese Water Dogs

• Doberman Pinschers

Symptoms to Watch For

One of the most dangerous aspects of hemangiosarcoma is how silently it progresses. Dogs often show no signs until the cancer is advanced or a tumor ruptures. Symptoms may include:

• Lethargy and sudden weakness

• Pale gums (a sign of internal bleeding)

• Abdominal swelling or bloating

• Sudden collapse or fainting

• Rapid or labored breathing

• Unexplained weight loss

• Dark, tarry stools

If your dog shows these signs, seek veterinary help immediately.

Prevalence and Survival

Hemangiosarcoma accounts for about 5–7% of all canine cancers. Alarmingly, studies show that one in five Golden Retrievers may develop this disease.

Survival outcomes vary:

• Without treatment: Days to weeks

• With surgery only: 1–3 months

• With surgery + chemotherapy: 6–9 months

• With newer therapies: Potentially longer, though research is ongoing

How Hemangiosarcoma is Diagnosed

Because this cancer often develops silently, regular veterinary care is crucial. Common diagnostic tools include:

• Ultrasounds and X-rays

• Echocardiograms (for heart tumors)

• Blood tests (to check for anemia)

• Biopsies or fine-needle aspirations

Treatment Options

While hemangiosarcoma is difficult to treat, there are options that may extend your dog’s life and improve quality of life.

1. Surgery – A splenectomy (removal of the spleen) is common, though rarely curative on its own.

2. Chemotherapy – Doxorubicin-based chemotherapy is often recommended after surgery to slow cancer spread.

3. Immunotherapy & New Treatments – Clinical trials are exploring vaccines and targeted therapies that may bring hope for the future.

4. Palliative Care – For families who choose not to pursue aggressive treatment, supportive care, pain management, and holistic therapies can bring comfort.

Preventive Measures and Early Detection

While there is no guaranteed way to prevent hemangiosarcoma, you can help your dog by:

• Scheduling regular veterinary checkups

• Screening high-risk breeds with ultrasounds

• Supporting your dog’s immune health with a balanced diet, exercise, and supplements

Finding Hope and Support

A hemangiosarcoma diagnosis can feel overwhelming, but you are not alone. At Kali’s Wish Cancer Foundation, we provide resources, education, and a compassionate community dedicated to offering pet cancer support. Whether you’re looking for treatment guidance, emotional support, or simply reassurance, our mission is to help families facing pet cancer.

By raising awareness and supporting advancements in veterinary oncology, we move closer to better treatment options and hope for pets affected by this devastating disease.