Hemangiosarcoma in Cats and Dogs
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 6/7/09
What are hemangiosarcomas?
Hemangiosarcoma (also known as hemangioendothelioma or angiosarcoma) is a malignant soft tissue sarcoma cancer
that arises out of blood vessels. It may be present as a single tumor or as multiple tumors, and often ruptures and bleeds.
It occurs more frequently in dogs compared to other species and is mostly seen in middle-aged to older animals. German
Shepherds, Golden retrievers, and Labrador retrievers appear to be at higher risk.
How common are these tumors?
Hemangiosarcoma (HSA) represents about 5% of all non-skin malignant cancers in dogs, 2.3-3.6% of skin tumors in dogs,
45-51% of spleen cancers in dogs and 2% of all cancers in cats. The most common organ that develops
hemangiosarcoma in the dog is the spleen (for more details, please see the Spleen Hemangiosarcoma section) but other
sites have been reported such as the heart (for more details, please see the Heart Hemangiosarcoma section), skin, liver,
lung, kidneys, mouth, muscle, bone, bladder, uterus. In the cat, hemangiosarcoma has been reported equally in the skin,
spleen, liver, and intestine, and less frequently in the heart, chest cavity, and nasal cavity. Skin hemangiosarcoma has a
tendency to develop in dog's light-haired or poorly pigmented skin.
What are the symptoms?
The symptoms will vary depending on the tumor's location. They can range from nonspecific signs to abdominal swelling
to acute death due to bleeding. Common symptoms for hemangiosarcoma (HSA) of internal organs include sudden
weakness or collapse, but can also be vague such as chronic weakness, lack of appetite or weight loss. Dogs with heart
hemangiosarcoma typically show signs of exercise intolerance and shortness of breath. More advanced skin
hemangiosarcomas can have a bruised appearance and can, therefore, be mistaken for a bruise.
How is the diagnosis made?
The tests used to diagnose hemangiosarcomas include blood and serum biochemistry tests, blood clotting test,
ultrasound and other imaging studies if necessary. Blood tests of pets with HSA will often reveal deficiency of red blood
cells. As is the case with all types of cancers, the definitive diagnosis of hemangiosarcoma requires biopsy.
Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as well
as by the treatments. To learn more, please visit the Cancer Pain Management section.
What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition section.
What are the treatment options?
Surgery has been the treatment of choice for hemangiosarcomas (HSAs). Surgical removal of a bleeding mass can
provide relief from clinical signs for some time, but does not significantly improve overall survival time. Chemotherapy
drugs (doxorubicin with or without vincristine/cyclophosphamide) have recently become important for treatment of HSA.
Radiation therapy is rarely used, but can be applied in some cases such as to control bleeding masses that cannot be
surgically removed. This treatment may help controlling clinical signs but has not been shown to significantly improve
survival time.
Are there any clinical trials investigating new treatments?
There are only a few available clinical trials investigating new treatments for spleen hemangiosarcomas in dogs. To learn
more about clinical trials open to enrollment in the United Statess, please visit Clinical Trials for Spleen Hemangiosarcoma
section. To learn more about veterinary clinical trials in general, please visit the Pet Clinical Trials section.
To help Pet Cancer Center conduct more hemangiosarcoma clinical trials across the United States in order to make novel
and more efficacious therapies available to pets, please
What is the prognosis?
The prognosis of a pet diagnosed with hemangiosarcoma will depend on how advanced the tumor is and the location.
Hemangiosarcomas are very aggressive tumors in dogs with a rapid onset of metastasis (spread) to other organs. The
most frequent organs to which hemangiosarcomas metastasize are the liver and lungs, but they have also been reported
to spread to the kidneys, muscle, lymph nodes, adrenal glands, and brain. In cats, skin hemangiosarcoma tumors are
considered less aggressive and behave similarly to other soft tissue sarcomas, but hemangiosarcomas of internal organs
have a high metastatic rate similar to dogs. The prognosis for pets with spleen HSA is poor despite aggressive surgical,
drug, or radiation therapy.
Median survival times for spleen HSA treated with surgery alone range from 19 days to 3 months, and less than 10% of
animals are alive one-year after surgery. Chemotherapy either with a single agent doxorubicin protocol or with a
combination drug protocol following spleen removal has been reported to increase the median survival time to 140 to 202
days. One study showed that adding immunotherapy increased survival to a median of 273 days. Cutaneous HSAs have
a better prognosis, with a median survival time of 780 days following surgery.
Additional online resources about hemangiosarcoma in pets:
Sources:
Hemangiosarcoma (also known as hemangioendothelioma or angiosarcoma) is a malignant soft tissue sarcoma cancer
that arises out of blood vessels. It may be present as a single tumor or as multiple tumors, and often ruptures and bleeds.
It occurs more frequently in dogs compared to other species and is mostly seen in middle-aged to older animals. German
Shepherds, Golden retrievers, and Labrador retrievers appear to be at higher risk.
How common are these tumors?
Hemangiosarcoma (HSA) represents about 5% of all non-skin malignant cancers in dogs, 2.3-3.6% of skin tumors in dogs,
45-51% of spleen cancers in dogs and 2% of all cancers in cats. The most common organ that develops
hemangiosarcoma in the dog is the spleen (for more details, please see the Spleen Hemangiosarcoma section) but other
sites have been reported such as the heart (for more details, please see the Heart Hemangiosarcoma section), skin, liver,
lung, kidneys, mouth, muscle, bone, bladder, uterus. In the cat, hemangiosarcoma has been reported equally in the skin,
spleen, liver, and intestine, and less frequently in the heart, chest cavity, and nasal cavity. Skin hemangiosarcoma has a
tendency to develop in dog's light-haired or poorly pigmented skin.
What are the symptoms?
The symptoms will vary depending on the tumor's location. They can range from nonspecific signs to abdominal swelling
to acute death due to bleeding. Common symptoms for hemangiosarcoma (HSA) of internal organs include sudden
weakness or collapse, but can also be vague such as chronic weakness, lack of appetite or weight loss. Dogs with heart
hemangiosarcoma typically show signs of exercise intolerance and shortness of breath. More advanced skin
hemangiosarcomas can have a bruised appearance and can, therefore, be mistaken for a bruise.
How is the diagnosis made?
The tests used to diagnose hemangiosarcomas include blood and serum biochemistry tests, blood clotting test,
ultrasound and other imaging studies if necessary. Blood tests of pets with HSA will often reveal deficiency of red blood
cells. As is the case with all types of cancers, the definitive diagnosis of hemangiosarcoma requires biopsy.
Do these tumors cause pain?
It is imperative that pets with cancer are provided with pain medication to relieve discomfort caused by the disease as well
as by the treatments. To learn more, please visit the Cancer Pain Management section.
What food should be fed to pets with cancer?
Pets with cancer need to be fed diets specifically designed to support a cancer patient. To learn more, please visit the
Cancer Nutrition section.
What are the treatment options?
Surgery has been the treatment of choice for hemangiosarcomas (HSAs). Surgical removal of a bleeding mass can
provide relief from clinical signs for some time, but does not significantly improve overall survival time. Chemotherapy
drugs (doxorubicin with or without vincristine/cyclophosphamide) have recently become important for treatment of HSA.
Radiation therapy is rarely used, but can be applied in some cases such as to control bleeding masses that cannot be
surgically removed. This treatment may help controlling clinical signs but has not been shown to significantly improve
survival time.
Are there any clinical trials investigating new treatments?
There are only a few available clinical trials investigating new treatments for spleen hemangiosarcomas in dogs. To learn
more about clinical trials open to enrollment in the United Statess, please visit Clinical Trials for Spleen Hemangiosarcoma
section. To learn more about veterinary clinical trials in general, please visit the Pet Clinical Trials section.
To help Pet Cancer Center conduct more hemangiosarcoma clinical trials across the United States in order to make novel
and more efficacious therapies available to pets, please
What is the prognosis?
The prognosis of a pet diagnosed with hemangiosarcoma will depend on how advanced the tumor is and the location.
Hemangiosarcomas are very aggressive tumors in dogs with a rapid onset of metastasis (spread) to other organs. The
most frequent organs to which hemangiosarcomas metastasize are the liver and lungs, but they have also been reported
to spread to the kidneys, muscle, lymph nodes, adrenal glands, and brain. In cats, skin hemangiosarcoma tumors are
considered less aggressive and behave similarly to other soft tissue sarcomas, but hemangiosarcomas of internal organs
have a high metastatic rate similar to dogs. The prognosis for pets with spleen HSA is poor despite aggressive surgical,
drug, or radiation therapy.
Median survival times for spleen HSA treated with surgery alone range from 19 days to 3 months, and less than 10% of
animals are alive one-year after surgery. Chemotherapy either with a single agent doxorubicin protocol or with a
combination drug protocol following spleen removal has been reported to increase the median survival time to 140 to 202
days. One study showed that adding immunotherapy increased survival to a median of 273 days. Cutaneous HSAs have
a better prognosis, with a median survival time of 780 days following surgery.
Additional online resources about hemangiosarcoma in pets:
- www.vet.uga.edu/vpp/clerk/frankhauser/index.php
- www.caninecancerawareness.org/html/CanineCancerHemangiosarcoma.html
- www.marvistavet.com/html/hemangiosarcoma.html
Sources:
- www.veg.uga.edu/vpp/cler/frankhauser/index.php
- Withrow Stephen J, and David M. Vail. Small Animal Clinical Oncology. St Louis: Saunders Elsevier, 2007.
- Morrison Wallace B. Cancer in Dogs and Cats: Medical and Surgical Management. Baltimore: Williams&Wilkins,
1998.
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