Canine hemangiosarcoma in dogs is often fatal.

Stages & Symptoms of Hemangiosarcoma in Dogs

Hemangiosarcoma in dogs is a cancer of the blood vessel walls. This type of cancer tends to most commonly affect the spleen and heart (angiosarcoma) of golden retrievers, Labrador retrievers, and German shepherds. Other breeds susceptible include Portuguese Water Dogs, Bernese Mountain Dogs, Boxers, and others.

Hemangiosarcoma does not cause dogs pain. Unfortunately, there are few symptoms and if the disease is found it most often has already metastasized.

The cause of hemangiosarcoma is not fully understood.

“It is estimated that this cancer accounts for more than 5 – 7% of all tumors in dogs.”

American Kennel Club Canine Health Foundation
Canine Hemangiosarcoma – The Road from Despair to Hope
Michelle G. Ritt, DVM, DACVIM; Tessa Breen, BSc (Hons), Dip GD, CMM

Hemangiosarcoma is an incurable tumor of cells (vascular endothelial cells) that line the blood vessels. It can present in different areas of the body, but are most commonly found in the heart or spleen.

Not a lot is understood about the risk factors of hemangiosarcoma; however, it’s thought that it might be inherited, the result of long-term ultraviolet exposure in lightly pigmented/short-haired breeds, genetic flaws, or the abnormal development of new blood vessels.

Typically, this type of cancer is seen in middle-aged to senior dogs between the ages of 9 and 12.

The One Ray of Hope in an Otherwise Deadly Disease

Dermal hemangiosarcoma can be considered curative if found, and removed, very early before it has had time to spread. If you see or feel any type of suspicious lump on your dog it’s important to have it aspirated by a licensed veterinarian.

Lumps and bumps on a dog must be evaluated by a licensed veterinarian in order to get a clear diagnosis.

Early detection of dermal hemangiosarcoma on a dog are key to long-term survival. If not diagnosed and removed early, approximately 33% of these tumors will spread to internal organs.

Best Case Survival Rates for Dogs with Hemangiosarcoma

Effectively treating this type of aggressive cancer is challenging at the best of times. If discovered early, surgical removal along with chemotherapy and radiation can help to extend your dog’s life.

However, the nature of this particularly malignant cancer means that survival time could be as low as 3 to 5 months.

If you’re unfortunate enough to be faced with this decision, consider your dog’s quality of life post surgery.

Asking a few key questions (seen below) can help you make one of the hardest decisions of your life.

“Considering the lifetime risk of cancer for dogs is between 1 in 2 and 1 in 3 , we can calculate that 1.5 to 2.5 million of the 72 million pet dogs in the United States today will get hemangiosarcoma and succumb to it.”

Jaime F. Modiano, VMD, PhD, Michelle G. Ritt, DVM, DACVIM, Matthew Breen, PhD, CBiol, MIBiol and Tessa Breen, BSc (Hones), Dip GD, CMM
University of Colorado Health Sciences Center, Denver, CO (JFM), Animal Hospital Center, Highlands Ranch, CO (MGR), and North Carolina State University (MB, TB)
Stages 1 Hemangiosarcoma in Dogs means the cancer hasn't spread.
Thank you to: shawn-pang-bIdKmDEIXcU-unsplash

Hemangiosarcoma Symptoms in Dogs

The signs of hemangiosarcoma in dogs are considered to be non-specific. Vague signs like the ones listed below could be caused by a variety of common illnesses in dogs. Unfortunately, it’s usually not until a tumor erupts and causes a severe internal bleed that the diagnosis is made.

Signs include:

  • Loss of appetite (also known as inappetence)
  • Weight loss
  • Fatigue
  • Unable to endure normal play/exercise
  • Vomiting
  • Diarrhea
  • Pale Gums
  • Increased breath rate/panting

Canine Hemangiosarcoma Stages

The stages of hemangiosarcoma are defined by where the cancer is found.

Stage 1 Hemangiosarcoma in Dogs

Tumor is found only in the spleen.

Stage 2 Hemangiosarcoma in Dogs

The splenic tumor has ruptured and may involve the lymph nodes.

Stage 3 Hemangiosarcoma in Dogs

At stage 3, the cancer has spread to the lymph nodes and other tissues.

When to Euthanize a Dog with Hemangiosarcoma

Unless your dog is diagnosed with signs of dermal hemangiosarcoma, the long-term prognosis is poor. The decision to euthanize a dog does not come easily, but it should be weighed with the dog’s quality of life.

When considering quality of life, determine whether your dog is still able to do the things he/she did before. Consider the following:

Level of Pain

Is your dog in pain and, if so, are medications able to alleviate some of that?


Is your dog still eating or able to keep food and water down?


Can your dog walk independently and is he/she able to go outside to use the bathroom without trouble?


Is your dog too ill to sit up, stand, walk to their food dish, etc.?

A failing dog will likely be very quiet and still. You may see a diminished personality and an aversion to things he/she used to love. When you dog gets to this stage, especially if he/she is in pain, it may be time to speak to a veterinarian about euthanasia.

Unfortunately, this is a very sad and difficult stage. You may feel guilt and anxiety about what to do. Your veterinarian may be able to provide feedback on the best time to do this for the sake of the dog.

Understanding What You’re Up Against

Hemangiosarcoma in dogs is a terrible disease. It’s aggressive, often spreads to the organs, and can be difficult to treat. However, there are some cases were dermal hemangiosarcomas have been cured by surgery. This requires early intervention.

This cancer can show up in the skin, spleen, liver, and heart. There are plenty of anecdotes about herbal remedies or natural approaches to treatment that may or may not have extended a dog’s life.

Keep in mind that many of these interventions have not been clinically studied or approved. In fact, some types of herbal or supplemental “treatments” could interfere with the effectiveness of chemotherapy.

The best place to go with questions about your dog’s health is to a licensed veterinarian.

I want to thank you for reading this post and ask if you could please take a second to Follow or Share. Believe me, it helps me to keep this blog up and running more than you could know.

Chondrosarcoma in Dogs Life Expectancy

Dog Spleen Tumors – Your Top Guide

Yunnan Baiyao for Dogs – 5 Crucial Things You Should Know


Veterinary Emergency & Clinical Care

University of Minnesota’s College of Veterinary Medicine

Scroll to Top