Hemangiosarcoma in Dogs

Hemangiosarcoma is a tumor of the blood vessel wall in dogs. Since there are blood vessels everywhere, these tumors can occur anywhere in the body. However, they occur much more commonly in certain locations in dogs, which include the spleen (by far the most common), liver and heart, and less commonly in the soft tissues including the skin, connective tissues, or muscle.

The symptoms of hemangiosarcoma are primarily hemorrhage from the affected site. When tumors occur internally, there are often no symptoms until hemorrhage causes a drop in blood pressure with weakness, lethargy, loss of appetite, and the sudden appearance of a distended belly. This event often requires an emergency examination at the veterinary clinic where a drop in red blood cells (anemia), low blood pressure, and blood in the abdomen is noted. The recommended next step is ultrasound where the veterinary specialists can examine all the internal organs and determine the source of the hemorrhage. The ultrasound is also necessary to determine if the cancer has spread to other organs. Thoracic radiographs allow assessment of spread of cancer in the lungs.

Surgery is recommended immediately when tumors occur in the spleen and visible masses are not seen anywhere else (chest or belly). A blood transfusion is often required during surgery. Dogs recovery well from removal of their spleen and have a good quality of life after surgery.

The concern in dogs diagnosed with hemangiosarcoma is that these are highly spreading tumors even though no visible masses were found during the dog's examinations. Dogs treated with surgery alone have a life expectancy of only 3-4 months, at which time additional bleeding masses are noted. Chemotherapy is recommended after removal of hemangiosarcoma to provide a longer quality of life for your dog. The protocol involves 2 drugs, Doxorubicin and Cyclophosphamide, given as injections and IV drips, every 3 weeks for 6 treatments to provide 9-12 months of quality life. Side effects are minimal and short lived when noted.

Hemangiosarcoma can also occur in the skin, connective tissues, and muscles and are often noted as hemorrhagic, purple masses. Surgery is recommended as the first line of treatment and special surgical skills may be required to remove the mass completely. Chemotherapy is recommended because these tumors are also spreading, although generally less so than the internal forms of hemangiosarcoma.