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The Heartbreak of Hemangiosarcoma in Dogs

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Introduction

It’s taken me two years to write a blog on this horrific cancer. I lost my heart dog Joey to this wretched cancer, so I have a special kind of hatred for it. Hemangiosarcoma (HSA) is a highly aggressive form of cancer that originates from the endothelial cells lining blood vessels, and it only affects dogs. It causes blood vessels to branch, fragment, become leaky, and ultimately rupture. Yup, pretty darn awful.

It is most commonly found in the spleen, liver, and heart of dogs, though it can occur anywhere in the body. This type of cancer is often referred to as a “silent killer” due to its rapid progression and lack of early symptoms. Hemangiosarcoma kills about 300,000 dogs in the U.S. annually. Let’s talk about how HSA is diagnosed and how you can try to keep your dog around as long as possible after diagnosis.

Why Do So Many Dogs Get Hemangiosarcoma??

Although the exact cause of hemangiosarcoma (HSA) remains unknown, genetic factors likely play a role, as certain dog breeds are more prone to this cancer. In humans, exposure to substances like arsenic and vinyl chloride has been linked to similar cancers.

A Link To Juvenile Spay/Neuter: Research has shown a concerning link between juvenile spay/neuter and the development of hemangiosarcoma (HSA) in dogs. A Swiss study indicated a higher risk of tumors outside the genital organs in neutered versus intact dogs. In a study of 2,505 Vizslas born between 1992 and 2008, females spayed at 12 months or younger had a ninefold increase in the odds of developing HSA compared to intact dogs, while both males and females neutered after 12 months also faced higher risks. Another study found that spayed females had over five times the risk of developing cardiac HSA and 2.2 times the risk of splenic HSA compared to intact females. Additionally, an upcoming study reviewing 5,736 dogs with HSA from 1964 to 2003 concluded that neutering increases the risk of splenic HSA and HSA in general, though not cardiac HSA. These findings underscore the need for careful consideration of the timing and necessity of spay/neuter procedures.

Human Comparisons: Similar tumors, called angiosarcomas, can occur in humans. These are often linked to environmental exposures such as vinyl chloride and polychlorinated biphenyls (PCBs) in industrial settings, or high-dose radiation treatments, such as those used in breast cancer therapy.

For my dog, Joey, I tried to do everything right… He ate a high quality raw diet, he ran daily with me, he was never treated with toxic pesticides and he was a “natural dog.” However, he was an avid grass eater and my neighbors sprayed pesticides on their lawns. He was also neutered at 6 months of age. I believe these two factors played a role in his development of Hemangiosarcoma.

Breed Predisposition

It occurs primarily in middle-aged to older dogs (mean 9.3-11 years), although it can develop in young (<3 years) animals. HSA occurs most often in large breed dogs such as German shepherds, golden retrievers, pitbulls and Labrador retrievers. However, small to medium breed dogs can also develop splenic HSA.

Hemangiosarcoma in dogs can manifest in three primary forms:

Splenic Hemangiosarcoma: This is the most common form, originating in the spleen.
Cardiac Hemangiosarcoma: This type occurs in the heart, typically affecting the right atrium. It can lead to pericardial effusion, where fluid accumulates around the heart, causing breathing difficulties, lethargy, and collapse.
Dermal/Subcutaneous Hemangiosarcoma: This form affects the skin and subcutaneous tissues. It may appear as dark red or black lumps on the skin, often in areas exposed to the sun.

Symptoms of Splenic or Cardiac HSA

Hemangiosarcoma often goes unnoticed until it reaches an advanced stage. The clinical signs are caused by bleeding of the tumor because it is a tumor of the vessels.

I had done an ultrasound of my two dogs who developed HSA every 6 months after the age of 6…and yet I still wasn’t able to catch it before bleeding occurred. The only symptom that Joey had was an acutely painful abdomen after running around the yard.

Early symptoms can be subtle and may include:

Lethargy
Loss of appetite
Weight loss
Pale gums
Abdominal swelling

As the disease progresses, more severe symptoms emerge, such as:

Collapse
Difficulty breathing
Sudden weakness
Seizures
Distended abdomen (due to internal bleeding)

Diagnostic Testing

Diagnosing hemangiosarcoma involves a combination of clinical signs, imaging, and laboratory tests:

Physical Examination: Initial assessment often reveals pale or white gums, weakness, collapse, distended abdomen with a fluid wave, rapid heartbeat and labored breathing.
Blood Tests: Complete blood count (CBC) and biochemistry panel to evaluate overall health and detect abnormalities.
Imaging: X-rays, ultrasound, and rarely CT scans are used to identify tumors and assess their size and location. Your vet will likely start with an x-ray and then recommend an ultrasound to pinpoint the organ of origin and look for metastasis.
Fine Needle Aspiration (FNA) or Biopsy: Collecting a sample of the tumor tissue for microscopic examination to confirm the diagnosis prior to surgery is not a common way to diagnose this cancer because of its propensity to bleed. Confirmation of diagnosis is usually when the dog has a splenectomy and it is submitted for biopsy. A liver biopsy is often performed at the time of splenectomy to rule out metastasis.
Echocardiogram: If pericardial effusion (fluid trapped between the heart and the cardiac sac) is suspected then a full echocardiogram is recommended to look for a small tumor. When a large breed dog presents in my ER for acute collapse the first thing I’m doing is taking them right into ultrasound to check for pericardial effusion.
Cytology: In blood smear cytology, about 80% of dogs with hemangiosarcoma show changes in red blood cell morphology. These changes can include irregularly shaped cells such as schistocytes, acanthocytes, and poikilocytes. Your vet may also find nucleated red blood cells in these samples. However, using a fine needle aspiration (FNA) to diagnose the mass is often unproductive. The samples are usually heavily diluted with blood, making it difficult to identify cancerous cells. Additionally, FNA is not recommended if there are coagulation problems, as it can risk spreading cancer cells within the abdomen.
Clotting testing: It is important for your vet to check clotting times especially if you plan to go to surgery. About half of the dogs with HSA also have a condition called disseminated intravascular coagulation (DIC), where the blood’s ability to clot and stop bleeding is severely impaired.

Staging Criteria for Canine Splenic HSA

Stage I: Unruptured tumor, <5 cm, confined to spleen
Stage II: Tumor ≥5 cm or ruptured, and/or with regional lymph node involvement, no distant metastasis
Stage III: Any size tumor with distant metastasis or invading adjacent structures

Treatment Options

The best outcomes of treatment are in dogs in which the tumor was found before a bleed, however, this is rare. See below about the University of Minnesota’s new study on early detection testing.

The treatment of hemangiosarcoma depends on the tumor’s location, stage of the disease, and overall health of the dog. When your dog first gets diagnosed, a bleak outlook will be discussed with you by the veterinarian. However, despite the poor prognosis, it is worth trying treatments in order to try to prolong your time together.

Surgery:
- Pre-Surgery Workup: It’s crucial to do full blood work, metastatic check radiographs, and an ultrasound of the heart to rule out metastasis before deciding on surgery.
- Tumor Removal: If the tumor is accessible and your dog is a good candidate, surgery is often the first step. A splenectomy (removal of the spleen) is common if the tumor is located there. I’ve performed splenectomies on dogs with benign tumors, though this is rare, so surgery can be a good option if it makes sense for your dog. However, even if you choose not to pursue surgery, it doesn’t necessarily mean the only other option is humane euthanasia. There are things you can try. See my treatment recommendations below.
- Heart Tumors: For heart tumors, pericardiocentesis (removing fluid around the heart) is often the first step. If there’s an ongoing bleed, the fluid may refill quickly, but if your dog stabilizes, surgery might be possible. Options include pericardectomy (removing part of the pericardium) or tumor removal, though the latter is high-risk with only about 15% survival during surgery.
- Skin Hemangiosarcoma: The prognosis for skin HSA is better than for visceral HSA. Aggressive surgery and chemotherapy can extend survival times, sometimes up to four years. If surgery requires narrow or dirty margins, radiation may be recommended.
Whole blood or packed RBC transfusions may be necessary pre-, intra-, or postoperatively. Plasma transfusions can increase survival times in patients with prolonged clotting times.
Chemotherapy: Post-surgical chemotherapy is an option. However, it’s not the route that I personally recommend. I did chemo on my German Shepherd with HSA, Gadden, 12 years ago. He only lasted 3 months post splenectomy. I did not pursue chemotherapy with Joey and he lasted 5 months. Results are variable depending on the dog, their condition and the extent of their disease.
Fidocure: Fidocure performs DNA sequencing on the tumor and identifies genetic mutations that may affect treatment. Fidocure then prescribes targeted therapies. Your vet can provide the tissue sample to FidoCure for DNA sequencing. I did this for Joey and I believe it contributed to extending his days with us.

New Hope with eBAT Testing: Researchers at the University of Minnesota have made a breakthrough in diagnosing hemangiosarcoma (HSA) before tumors develop. Building on this, they’ve created a drug called eBAT that significantly improves survival rates when used alongside early detection. eBAT was tested on 23 dogs of various breeds with HSA of the spleen. Dogs received three treatments of eBAT after surgery to remove the tumor and before conventional chemotherapy. The drug treatment improved the 6-month survival rate to approximately 70%. Furthermore, five of the 23 dogs that received eBAT treatment lived more than 450 days. eBAT represents one of the most significant advancements in canine HSA treatment in decades. eBAT is not yet widely available because it is still undergoing clinical trials to establish its safety, efficacy, and optimal use protocols.

A Multi-Layered Approach At Home: Time to Pull Out All The Stops

Yunnan Baiyao: This Chinese herb is my #1 go to my patients with HSA. It is utilized to help control bleeding in patients with hemorrhagic conditions. It works by inhibiting tumor angiogenesis, reducing vascular permeability, and promoting apoptosis in cancer cells, thereby slowing tumor growth and managing severe symptoms associated with the disease. Anecdotal dosage is 1 capsule/20 lb body weight. There is a little red emergency pill in the middle of these packets. This is to be given when symptoms of abdominal bleeding arise such as pale gums, weakness, imbalance, and distended abdomen. Additional capsules can also be given every 3-4 hours during a bleed to help get it under control. Pets must be kept as still as possible during these bleeds. No walking out to go to the bathroom… nothing. Complete stillness. This herb may be used in conjunction with other therapies for HSA.
Mushrooms: A study from UPenn in 2012 showed that dogs with hemangiosarcoma that were treated with a compound derived from the Coriolus versicolor mushroom had the longest survival times ever reported for dogs with the disease. This is the mushroom product the dogs were given in this study https://www.buyimyunity.com/humans#!/~/product/id=146624445 and it was given at high doses (100 mg/kg/day) .
Diet and Nutrition: A diet rich in antioxidants, omega-3 fatty acids, and high-quality proteins can support the immune system. Fresh, gently cooked diet or raw diet is best. A ketogenic diet is something to consider. Consider consulting with a holistic veterinarian to develop a suitable diet plan.
Homeopathy: Dr. Loops recommends “Ceanothus americanus and intermittent dosing with Carcinosin to prolong metastatic tumor appearance.” He also recommends Phosphorus 30C combined with Arnica montana 30C the most useful. In severe situations he recommends multiple doses of each of these. I consulted with Dr. Loops for Joey and he was so kind and helpful. Here is a link to his website https://www.charlesloopsdvm.com/home.
Vitamin C: Large doses of vitamin C may help cancer patients by enhancing the immune system, reducing inflammation, and potentially improving the effectiveness of certain cancer treatments by increasing oxidative stress on cancer cells
CoQ10: CoQ10 may help cancer patients by boosting cellular energy production, enhancing immune function, and potentially reducing the side effects of chemotherapy.
Liver support: The liver is one of the first places we will see metastasis of hemangiosarcoma. I like to detox and support the liver as much as possible in HSA patients. You can do this by adding Milk Thistle and S-adenosyl-methionine (SAMe).
Turmeric: Turmeric’s active compound, curcumin, which has anti-inflammatory and antioxidant properties. Curcumin can inhibit the growth of cancer cells, reduce the spread of tumors, and enhance the effectiveness of chemotherapy by sensitizing cancer cells to the treatment. Additionally, it may protect healthy cells from the damage caused by radiation therapy
Green tea: may help fight cancer through its high content of catechins, particularly EGCG, which can inhibit tumor growth, induce cancer cell apoptosis, and prevent metastasis. Additionally, green tea may enhance the effectiveness of chemotherapy and reduce its side effects, making it a potentially powerful adjunct in cancer treatment strategies
Support your dog’s gut as it is 70-80% of their immune system: Add per and probiotics. The fresh diet as I previously mentioned. Test their gut with animal biome or VDI and follow guidelines to create a strong microflora
CBD oil: According to research and Angela Ardolino (the Queen of CBD), CBD for dogs with cancer has been shown to inhibit tumor growth, trigger cancer cell death via apoptosis, prevent the formation of blood vessels that feed tumors (angiogenesis), and discourage the spread of cancer to other parts of the body (metastasis).
Acupuncture: This traditional Chinese medicine technique can help manage pain, support the immune system and improve overall well-being. Joey loved his acupuncture

The Prognosis is Poor, However…

The prognosis for dogs with hemangiosarcoma is poor due to the aggressive nature of the disease. Less than 10% of dogs survive a year – even with treatment. However, the remedies discussed above have the potential to greatly increase your dog’s lifespan. Every dog, every patient, is different. So don’t let these statistics stop you from doing everything you can to keep your dog around as long as possible. Use this time to cherish your moments together. Go to your favorite places, lay on the floor together, make beautiful food for your dog. Take this time to fully show up and embrace this opportunity to give back to the dog that has given you so much.

Prevention

Preventing hemangiosarcoma in dogs can be challenging due to its elusive nature and rapid progression, often making early detection difficult. However, there are several proactive steps you can take to reduce the risk:

Consider sterilization instead of spay/neuter or at least delay spay/neuter procedures until your dog reaches maturity, as early spay/neuter has been linked to an increased risk of certain cancers.
Incorporating chlorella into your dog’s diet can be beneficial due to its powerful antioxidant and detoxifying properties, which help neutralize free radicals and remove harmful toxins from the body.
Minimizing your dog’s exposure to environmental toxins by avoiding chemical pesticides, using natural cleaning products, and providing clean, filtered water can further support overall health and reduce cancer risk.
Regular veterinary check-ups to try to catch changes in bloodwork or organ enlargement.
A diet rich in fresh, whole foods also contribute to maintaining a robust immune system and overall well-being.

Conclusion

Hemangiosarcoma in dogs is a heartbreaking diagnosis. Early detection, combined with a comprehensive treatment plan that includes conventional and natural remedies, can help improve your beloved friend’s quality of life and potentially extend their time with you. I recommend getting a team together that includes a great surgeon, a holistic vet, a homeopathic vet and when the time comes, a trusted home euthanasia vet.

The shock of diagnosing Joey with hemangiosarcoma still brings tears to my eyes as I write this… But what I can tell you is that, although it was such a sad time, it was also a beautiful time. Doing everything I possibly could to extend my sweet boy’s life brought us even closer, which I didn’t even think was possible. Those five months after diagnosis were a cherished, sacred time that I will hold close to my heart until he meets me at the rainbow bridge. When Joey arrived in my life, he showed me how to become a better doctor and as he left… he did it again.

Check out my tribute to Joey here.

My Tribute To Joey