Hey there, pet parents. Today we need to discuss a very serious and aggressive cancer that affects dogs, often with little to no warning: Hemangiosarcoma. This is a cancer of the cells that line the blood vessels, and because of this, it can appear anywhere in the body. It is a devastating diagnosis, and understanding its nature is important for any dog owner.
What is Hemangiosarcoma?
"Hema" means blood, "angio" means vessel, and "sarcoma" is a type of cancer that arises from connective tissue. So, hemangiosarcoma is a malignant tumor of the blood vessel lining.
Because it's a cancer of blood vessels, it can form anywhere, but there are three common primary locations:
- •The Spleen: This is by far the most common location. About 50% of all splenic masses in dogs are hemangiosarcomas.
- 1The Heart: Specifically, the right atrium of the heart is the second most common location.
- 2The Skin: Hemangiosarcoma can also appear as a lump on or under the skin.
The major problem with hemangiosarcoma is that the tumors are basically just big, fragile, blood-filled sacs. They have a very high tendency to rupture and bleed, and they also have a very high rate of metastasis (spreading to other parts of the body), especially the lungs and liver.
Breeds at Risk
Hemangiosarcoma is a disease of older dogs, and there is a strong breed predisposition.
- •German Shepherds
- •Golden Retrievers
- •Labrador Retrievers
Spotting the Signs: The Silent Killer
This is the most difficult part of hemangiosarcoma. In the early stages, there are often no signs at all. The dog seems perfectly healthy while the tumor is silently growing.
Often, the first sign an owner sees is when the tumor ruptures, leading to a sudden and catastrophic internal bleeding. The signs of a rupture are:
- •Sudden, severe weakness and collapse.
- •Pale gums.
- •A rapid, weak pulse.
- •A distended or swollen abdomen.
- •Difficulty breathing.
This is a life-threatening emergency. The dog is bleeding to death internally.
In some cases, there may be more subtle signs leading up to a major bleed, such as intermittent lethargy or weakness (as the tumor has a small bleed that the body reabsorbs), a decreased appetite, or weight loss.
For the skin form, the sign is simply a new lump or mass on the skin. The skin form that is related to sun exposure on thinly-haired skin has a much better prognosis than the other forms.
Diagnosis
If a dog presents with a collapse and suspected internal bleeding, the vet will move quickly.
- •Ultrasound: An emergency ultrasound of the abdomen (called an AFAST scan) will be performed to look for free fluid (blood) in the belly and to look for a mass on the spleen.
- •X-rays: Chest X-rays are crucial to check for any visible evidence of metastasis to the lungs.
- •Bloodwork: To check for anemia and other problems.
The definitive diagnosis is made by submitting the removed tumor tissue for a biopsy.
Treatment and Prognosis
The treatment and prognosis depend on the location of the tumor.
Splenic Hemangiosarcoma
- •Emergency Surgery: If a dog has a bleeding splenic mass, the only chance for survival is emergency surgery to remove the spleen (splenectomy). This is a high-risk surgery.
- •Chemotherapy: After surgery, chemotherapy is recommended to try to slow down the metastatic disease. The most common chemotherapy protocol uses a drug called Doxorubicin.
Unfortunately, even with surgery and chemotherapy, the prognosis for splenic hemangiosarcoma is very poor. The cancer is just too aggressive.
- •With surgery alone, the average survival time is only 1-3 months.
- •With surgery and chemotherapy, the average survival time is extended to 5-7 months.
Cardiac Hemangiosarcoma
The prognosis for hemangiosarcoma of the heart is even worse. The tumor can bleed into the sac around the heart (the pericardium), which prevents the heart from beating properly (a condition called pericardial effusion). Surgery to remove these tumors is rarely possible. The prognosis is typically only a few weeks to months.
Skin Hemangiosarcoma
The skin form has a much better prognosis. If the tumor is confined to the skin and can be completely removed with surgery, the dog can be cured.
Hemangiosarcoma is a truly awful disease. Because it is so silent in its early stages, there is often nothing an owner could have done differently. The focus is on emergency intervention and, ultimately, on quality of life.
Sources & Further Reading:
- •American College of Veterinary Surgeons - Splenic Hemangiosarcoma
- 1VCA Animal Hospitals - Hemangiosarcoma in Dogs