Hemangiosarcoma In Dogs: Symptoms, Causes, Treatment

Image of a young boy with his dog

Has your dog been recently diagnosed with hemangiosarcoma? While this may not be the best news, there are many things that you can do to help your dog live a long and happy life.

Your vet can also discuss the pros and cons and help you weigh all the different options that you have.

What is Hemangiosarcoma in Dogs?

Hemangiosarcoma is a malignant cancer of your dog’s blood vessels that can be anywhere from the skin to internal organs.

The most common internal sites are the spleen, heart, and liver. Hemangiosarcoma is the most common splenic tumor in dogs and is locally aggressive and highly metastatic, meaning it will spread to other organs very quickly and easily.

What Causes Hemangiosarcoma in Dogs?

The cause of hemangiosarcoma is unknown. It is thought to be caused by sunlight exposure if the mass occurs on the skin.

There are certain breeds that are more predisposed to this type of cancer. These are:

  • German Shepherds
  • Boxers
  • Golden Retrievers
  • Pointers
  • Labs

This type of cancer is most commonly seen in older large breed dogs. Most dogs who get hemangiosarcoma are at least eight years of age. This type of cancer can be seen in smaller dogs, too but is more common in large breed dogs.

Signs of Hemangiosarcoma

There are many signs that your vet would be looking at to indicate that your dog may have hemangiosarcoma. The common signs of hemangiosarcoma are:

  • Enlarged abdomen
  • Pale gums
  • Unexplained weight loss
  • Lower energy
  • Lethargy
  • Decrease in appetite
  • Panting
  • Collapse

If your dog has hemangiosarcoma of the skin, you will see a small red bump. These will be less than ½ an inch in size and may bleed very easily when touched.

If you notice any of these signs in your dog, it is best to take them to the vet right away. Your vet can examine your dog and see if they think that your dog may have hemangiosarcoma or another condition.

How Hemangiosarcoma in Dogs is Diagnosed

There are many different things that your vet may do to help them diagnose your dog with hemangiosarcoma. The only way to tell for sure if your dog does have hemangiosarcoma is to take a sample of the mass and send it to a veterinary pathologist for review. They will take a thin slice of the mass and look at it under the microscope.

There are other tests that would also lead your vet to conclude that your dog may have hemangiosarcoma. These tests are:

CBC and Blood Chemistry Panel

this would show that your dog has a low red blood cell count. This would indicate that your dog may have a mass inside that is bleeding.


Your vet may take x rays of your dog’s abdomen or chest and see a mass on the liver or spleen.

Abdominal Ultrasound

Your vet can ultrasound your dog’s abdomen to see if there is a mass on the liver or spleen. This will also help them determine if this mass is bleeding into your dog’s abdomen.

FNA and cytology

If your vet can get a good view of the mass with the ultrasound, they can stick a small needle into the mass and take a few cells. Your vet can look at these cells under the microscope to see if they see cells that have cancerous properties.


The best way to tell if your dog has hemangiosarcoma is to do surgery to remove the mass and send it to a veterinary pathologist. While this is the most invasive and most expensive way to tell what type of tumor your dog has, it is the most accurate.

Stages of Hemangiosarcoma in Dogs

There are different stages of hemangiosarcoma in dogs. This depends on how aggressive the tumor is and where it has spread to in your dog’s body.

These are the three stages of hemangiosarcoma in dogs:

  • Stage 1: The mass is only in the spleen
  • Stage 2: The splenic mass is ruptured with local lymph node involvement
  • Stage 3: The mass has spread to distant lymph nodes

The more aggressive the mass is, the higher the grade—also, the higher the grade, the worse the prognosis and life expectancy for your dog.

Pain Caused by Hemangiosarcoma in Dogs

Usually, this type of tumor can cause your dog to be lethargic and have to undergo very invasive surgery. This type of surgery may be painful. Your vet will make sure that your dog has pain medication to help keep them comfortable while they are recovering from surgery.

Dogs who have an internal mass may be painful from the bloated and distended abdomen. These masses will take up space in your dog’s abdomen and can cause them to be uncomfortable when they are walking or lying down. If you notice that your dog is experiencing pain, it’s best for your vet to examine your dog to figure out what’s causing it.

Treatment for Hemangiosarcoma in Dogs

There are many different treatments for hemangiosarcoma. There are surgery and/or chemotherapy combinations that are usually used in treating hemangiosarcoma.


A splenectomy is the treatment of choice for hemangiosarcoma in the spleen, the main organ affected by this type of cancer. Depending on how involved the mass is, other organs can be partially removed. Your dog can live without part of their liver, and if a certain part is effective can easily be removed.


Chemotherapy is usually used after a splenectomy to help prevent or treat any part of a tumor that has spread to other organs in the body. With the use of chemotherapy and surgery, you can help increase the survival time in dogs with hemangiosarcoma. The majority of dogs will tolerate chemotherapy very well and will maintain a good to the excellent quality of life even during chemotherapy treatment.

A drug called doxorubicin is the most commonly used chemotherapy drug to treat dogs with hemangiosarcoma. Your dog will receive a chemotherapy injection every three weeks for 5 to 6 dosages. This is usually started a few weeks after surgery. This is a medication that has to go in your dog’s vein, so they most likely will need to spend the day at the vet clinic.

Some chemotherapy is only done by a veterinary oncologist. So your vet may refer your dog to a veterinary oncologist for their chemotherapy treatment. A veterinary oncologist has had specialized training beyond veterinary school to help them treat and manage cancers.

There are other chemotherapy drugs that can be used to treat your dog with hemangiosarcoma. Your vet can determine the best route of treatment. Many people think of chemotherapy in the dog as the same as in people, but it’s actually very different. Most dogs do not have the same side effects that we think of with people because the dosages are not as high.

Discuss the pros and cons of the different chemotherapy options with your vet.

Supplements that May Help with Hemangiosarcoma

There are some supplements that you can give to your dog to help them with hemangiosarcoma. Many supplements are being studied at many veterinary schools in the US into their effectiveness for conditions like hemangiosarcoma in dogs. These are some common supplements that your veterinarian may prescribe for your dog to take.

Yunity Polysaccharopeptide (PSP) Mushrooms

These are Asian mushrooms that are mixtures of mushroom-derived polysaccharides. The bioactive agent is from mushroom Coriolus Versicolor, but the brands are usually proprietary blends.

Some research indicates that these mushrooms may cause cancer cells to die and have other anti-cancer properties. A study done at the University of Pennsylvania has shown that giving dogs these mushrooms after splenic removal will help increase the survival time. Dog’s survival rate increase from 86 days to 199 days.

Yunnan Baiyao

This is a Chinese herbal root mixture. Yunnan Baiyao claims to decrease bleeding and has hemostatic properties, activates platelets, and decreases bleeding and clotting times.

Yunnan Baiyao is one of the most popular Chinese herbs used in veterinary medicine for hemorrhage. It is known to stop bleeding anywhere within the body. It has even been shown to decrease clotting times and initiate the release of platelets. Platelets are responsible for clot formations in your dog’s body.

The recommended dose for hemangiosarcoma is 60-75 mg/kg daily or 1/4 tsp. per 10 -15 pounds divided twice a day.

There are many other supplements that are currently being studied, and hopefully, in the future, there will be many other treatment choices that will increase the survival time and quality of life for dogs with hemangiosarcoma.

What is the prognosis and life expectancy for hemangiosarcoma?

Unfortunately, the prognosis for hemangiosarcoma in dogs with surgery alone is poor. The median survival time in dogs treated with only surgery is 1 to 3 months, and less than 10% of dogs will survive one year. Chemotherapy improves the survival time to 6 months, using a doxorubicin-based protocol. Low-grade tumors may have a better prognosis, especially when chemotherapy is given after surgery.

Final Thoughts

If your dog is diagnosed with hemangiosarcoma, there are options that you have to help extend their quality and quantity of life. There are surgical and chemotherapy options along with supplements and other daily medications that you can give to your dog to help.

If you suspect that your dog may have this type of tumor, it would be best to see your vet as soon as possible. With hemangiosarcoma, it is best to start treatment as soon as possible to help prevent the spread to other organs and help increase your dog’s life. Frequent vet visits can help catch this type of tumor before they become more serious.