What is it?
Hemangiosarcoma is a form of cancer originating in the endothelium which occurs
more frequently in dogs than in any other species.
Because hemangiosarcomas start in the blood system, and because blood
vessels are necessary in almost all body tissues, they are highly malignant
and can travel to almost any part of the body. The spleen, heart and
pericardium are most often affected, with the liver and skin being less often
involved. This type of
cancer tries to build blood vessels in a haphazard fashion which essentially
causes blood blisters to form and disrupts normal organ function. The blood
blisters also rupture easily causing bleeding from the cancer sites.
This is a highly malignant type of cancer, and an extremely metatastic one.
Almost all dogs diagnosed with hemangiosarcoma will develop metastases within
six months of their being diagnosed. The most common place for hemangiosarcoma
to metastasise to is the brain, but it can also spread to the lungs, liver,
spleen, heart, kidneys, skeletal muscle and bone.
On examination, the tumour can be of varying sizes (sometimes
weighing as much as ten or more pounds when they affect the spleen) and can be
coloured pale grey through to dark red. They are nodular in form and soft to
touch. Because these tumours can rupture within the body, when examined they
may have visible signs of these ruptures and of necrosis.
Hemangiosarcomas are poorly-formed, non-encapsulated and often adhere to
Who Gets it?
Older dogs (over six years of ages) of larger breeds are affected by
hemangiosarcoma more than any other dogs. Within that grouping, German
Shepherds, Golden Retrievers and black dogs of any breed get
hemangiosarcoma more often than other types. More male than female dogs
My vet tells me that German Shepherds and Black dogs make up more than 90% of
her patients with hemangiosarcoma.
What are the symptoms?
Most commonly, the families of dogs affected by hemangiosarcoma will not be
aware of any great problem until the disease has progressed too far to be
successfully treated. The dog will seem well (particularly if the primary site
is the spleen) until the tumour ruptures. If this rupture is slight, the dog may
seem very tired and will have very pale gums and eyelids. If the rupture is more
severe, the dog may simply die.
Some symptoms which may occur are:
Any tumour in the spleen or heart, particularly in a larger, older dog, will
make the veterinarian highly suspicious of the presence of hemangiosarcoma. He
will check the dog for signs of anemia (pale gums and eyelids) and need to be
told how the dog has been behaving in the last few days or weeks.
Often, he will take an x-ray or ultrasound of the dog and order other
tests with can include:
Diagnosis is accomplished by biopsy or removal of the tumor. This can be
difficult because there may be multiple tumors present, the primary tumor site
may prove challenging to determine, and there is great risk of severe hemorrhage.
Tumours on the spleen and even on the heart may be possible to remove while they
are small. In some cases this will prolong the dog's comfortable life, but often
by the time the tumours are discovered it is too late for this to be of much
No hemotheraputic or radiation treatments have been found to be very
effective on this type of cancer as yet, although some dogs treated with
chemotherapy and drugs including cyclophosphamide, vincristine, doxorubicin
and cytoxan do live a little longer than those who are not.
Long-term prognosis of dogs with hemangiosarcoma is poor.
Studies have shown that surgery alone, usually a splenectomy, offers a median
survival time of 19-83 days.
Dogs with splenic tumours which have ruptured generally live a shorter time
A combination of splenectomy and chemotherapy can increase survival time up
to a year in less than 10% of cases.
- 43% of dogs with splenic masses have hemangiosarcoma (HSA)
- 50% of dogs with splenic HSA are in DIC at presentation
- Average post-splenectomy survival times reported are: 49-120 days
- Liver biopsy is essential to differentiate between liver metastasis and
- Shepherds and northern breeds are at increased risk for developing HSA
- Stage I cutaneous HSA can be cured with aggressive surgical resection
- Three views of the lungs are required to rule out pulmonary metastasis
- Cardiac HSA is the most common cause of pericardial effusion in dogs.
- Chemotherapy significantly increases average survival time in dogs with
- HSA in cats is rare but occurs most commonly within the abdomen or