Hemangiosarcoma in Dogs

Hemangiosarcoma is more common in dogs than any other animal species and is one of the most predominant forms of canine cancer. Also known as Angiosarcoma or malignant Hemangioendothelioma, it originates in the endothelium, which is the top layer of tissue surrounding the dog’s blood vessels, lymph nodes and heart. Hemangiosarcoma invades the blood vessels; it can appear just about anywhere in or on the body. Hemangiosarcoma of the spleen is the most common form of this cancer. A diagnosis of Hemangiosarcoma should be treated seriously, as the tumors can lead to internal and external bleeding and other health problems associated with the bleeding.

What are the types of Hemangiosarcoma in dogs?  

  1. Dermal Hemangiosarcoma appears on the skin. This type has the highest chances of recovery and is the easiest to remove. It appears as red or black growths on the skin and is most often associated with exposure to the sun, forming on areas that are naked or lightly furred. Dogs with short white fur are more susceptible. Early detection will result in better outcomes and survival rates.
  2. Subcutaneous (hypodermal) Hemangiosarcoma occurs under the top layer of skin and appears as dark red blood growths. Sixty percent of this type metastasizes and spreads internally.
  3. Visceral Hemangiosarcoma most often affects the spleen and the heart but can also affect the liver, lungs, kidneys, muscle tissue, bone, uterus and bladder. Tumors forming on the spleen often tend to break and bleed profusely. Bleeding from heart-based tumors is also life-threatening, as blood from a rupture can fill the heart sac, putting extra pressure on the heart and preventing it from beating properly. This condition is known as pericardial effusion and can lead to serious health complications.

What are the symptoms of Hemangiosarcoma?

Symptoms will depend on the location of the disease. For example, Hemangiosarcoma in the skin will show as a mass or lump under the skin. The lump may bleed or become ulcerated. Hemangiosarcoma in the spleen or liver can show clinical signs such as weakness, anemia, collapse, and pale gums. Heart-based Hemangiosarcoma can cause weakness, breathing difficulties, intolerance to exercise, fluid buildup in the abdomen and abnormal heart rhythms. Other general symptoms include loss of appetite, lethargy, vomiting, and weight loss.  

What are the causes of Hemangiosarcoma?

Hemangiosarcoma is rare in humans, and as a result, there isn’t much research about it or its causes. As of the writing of this blog, researchers believe that Hemangiosarcoma is tied to genetics and environmental factors. The dermal form of the disease is associated with excessive exposure to sunlight. This form of cancer is more common in certain breeds including Golden Retrievers, Labrador Retrievers, German Shepherds, Boxers, English Setters, and Doberman Pinschers. Canine Hemangiosarcoma usually occurs more often in older dogs; males tend to be more susceptible than females. There is also now evidence that spaying and neutering (particularly when performed early in life before full maturity is reached) increases the risk of the disease. Studies confirm an association between neutering and development of splenic Hemangiosarcoma but not cardiac Hemangiosarcoma, in both male and female dogs.[1]

How is Hemangiosarcoma diagnosed?

A basic physical examination can uncover signs that the disease may be present. For example, pale or white colored gums can signal anemia. An abdominal exam will look for lumps or swelling. A complete blood test will detect signs of low platelet counts. An activated clotting test can signal a bleeding disorder. Ultrasonography can reveal tumors in the spleen, liver, heart, or other organs.  An echocardiogram will detect masses in the heart. The gold standard for diagnosis is a biopsy. Since the most accurate results are based on the primary tumor, it can be challenging to get an accurate confirmation if there are multiple tumors.

How is Hemangiosarcoma treated?

Treatment will depend on the location of the cancer as well as its spread. Conventional treatment of Dermal Hemangiosarcoma involves surgical removal of a tumor on the skin; this can be followed up with radiation therapy and/or chemotherapy. This type of cancer can often be cured with surgery alone (8 out of 10 dogs); however, if the tumor is deep in the skin, the success rate is much lower. 

Visceral forms of Hemangiosarcoma are much harder to treat. Treatment of Splenic Hemangiosarcoma can include removal of the spleen if the tumor is identified early. Less than 10% of the dogs survive more than a year after surgery. Tumors near the heart can also be removed. These procedures may prolong the life of your pet. Surgery alone is rarely helpful in these cases because of the highly aggressive nature of the cancer. Conventional post-surgery treatment can include radiation and/or chemotherapy. Other treatments are aimed at soothing symptoms, stopping any bleeding problems, and providing supportive care to ensure comfort.  

 In 2021, the National Canine Cancer Foundation (NCCF) funded part of the research being done at the University of Minnesota that has led to a breakthrough in treating this dreaded disease. In Phase 1 of the study, researchers developed a blood test to diagnose Hemangiosarcoma with 90% accuracy. In Phase 2, the test was used to determine whether the disease had returned in a dog being treated for the disease. Results are ongoing but suggest that the test can indeed detect a return of the disease. Data in this phase are still being collected and analyzed. 

 The research by the University of Minnesota and the NCCF is providing hope for dogs diagnosed with Hemangiosarcoma. In addition to the diagnostic test developed in 2021, a University of Minnesota professor has invented a drug that specifically targets tumors while causing minimal damage to the immune system. The drug, named eBAT, was used in a trial of 23 dogs. The dogs were given 3 doses of eBAT following surgery to remove splenic tumors. The use of eBAT improved the 6-month survival rate to approximately 70%, while 5 of the 23 dogs survived to more than 1 year.[2]

Can Hemangiosarcoma be prevented?

Research on the causes of Hemangiosarcoma is limited. As a result, prevention protocols are limited. The statistics are sobering – only 10% of dogs will survive one year past their diagnosis. Less than 50% will survive 4-6 months past diagnosis. However, in Phase 3 of the University of Minnesota study, called “Shine On,” researchers are focusing on how effective the test is at detecting Hemangiosarcoma in its earliest stages with the goal of preventing the disease in healthy dogs. The researchers estimate that there is a less than 1% chance of an “at-risk” dog that tests “negative” to develop Hemangiosarcoma over a subsequent 6-month period. These dogs are considered candidates for “prevention.”[3]  Prevention is achieved by using eBAT to kill the cells that create and maintain the tumor and to make conditions unfavorable for tumor growth. The drug eBAT has been proven to be safe and potential side effects are manageable.

The University of Minnesota research will continue and the results will continue to be disseminated through scientific and veterinary meetings, as well as through scientific, peer-reviewed publications. In the meantime, there are many options and factors to consider with a Hemangiosarcoma diagnosis. When in doubt, talk to your family, your veterinarian, and veterinary specialist to find the best option for you and your pet. Ask them if they are aware of the latest diagnostic tools and lifesaving treatments like eBAT.

What can be done from a holistic perspective?

  1. Feed a species-appropriate, human-grade diet
  2. Turkey tail mushroom supplements
  3. Yunnan Bai Yao
  4. Homeopathic phosphorous
  5. Vitamin C
  6. CoQ10
  7. IP6
  8. Milk Thistle
  9. Turmeric or Golden Paste
  10. Probiotics/Prebiotics
  11. CBD


[1] Pubmed.ncbi.nlm.nih.gov/32355348/

[2] https://aacrjournals.org/mct/article/16/5/956/92284/Safe-and-Effective-Sarcoma-Therapy-through-Bispecific-Targeting-of-EGFR-and-uPAR

[3] https://wearethecure.org/breakthrough-in-hemangiosarcoma-treatment-in-dogs)


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