HEMANGIOSARCOMA IN DOGS
Hemangiosarcoma (HSA) is a malignant cancer which arises from cells associated with blood vessels. Blood vessels are present throughout the body, and therefore HSA can be found anywhere. The most common site of HSA in the dog is the spleen (2/3 of splenic tumors are cancer and 2/3 of those are HSA). HSA also occurs frequently in the heart, liver, skin and subcutaneous tissue. HSA is a difficult type of cancer to treat, because it tends to metastasize (or spread) aggressively and quickly to local lymph nodes, abdominal organs, and lungs. HSA occurs most commonly in older dogs at an average age of 7-10 years. German Shepherd dogs, Golden Retrievers and Labrador Retrievers are commonly affected breeds.

Clinical signs
Hemangiosarcoma causes different clinical signs depending on its location. Because it is a tumor of blood vessels, bleeding often occurs. When HSA is located in the spleen, liver or another abdominal organ, bleeding into the abdomen can cause a distended belly (hemoabdomen), weakness and collapse (due to a sudden decrease in circulating blood, or anemia). When small bleeds occur, the blood may be reabsorbed by the body. This causes intermittent mild bouts of weakness. A very large amount of bleeding can lead to death in the most extreme cases. When hemangiosarcoma is located in the heart, bleeding can occur in the pericardium (the sac around the heart) leading to an inability of the heart to beat regularly and severe weakness or death. Tumors located in the subcutaneous tissue or the limbs can bleed leading to sudden swelling, bruising and pain.

Diagnosis
Hemangiosarcoma is definitively diagnosed with a tissue biopsy. Often the biopsy is obtained when a spleen is removed due to rupture of a tumor and intraabdominal bleeding (hemoabdomen). This surgery is often done on an emergency basis and the diagnosis is determined afterwards. For tumors located elsewhere, a needle biopsy or surgical biopsy can be done. Because there is often a large amount of swelling and bruising, it can be difficult to obtain a good sample with a needle biopsy instrument.

Clinical staging "Clinical staging" is a term which means doing diagnostic tests to determine the extent of disease in the body. This usually includes abdominal ultrasound to look at the liver, spleen, kidneys and other abdominal contents, as well as x-rays of the thorax to look for nodules in the lungs and evaluate the size of the heart. Ultrasound of the heart is sometimes done to look for evidence of a tumor. Blood work including a complete blood count and chemistry profile are done to evaluate the overall health of the animal. All of these tests may not be performed on an emergency basis in a dog with hemoabdomen.

Treatment
The treatment of choice for hemangiosarcoma is surgical excision of the primary mass when possible. If there are multiple masses, surgery may not be beneficial. Because we assume that HSA will always metastasize if it hasn't already, chemotherapy is also part of an aggressive treatment plan. In general chemotherapy is tolerated better in dogs than in people and adverse effects tend to be minimal. Our goal is for the pet to maintain a normal quality of life while on chemotherapy. If problems occur, we make changes in order to reach that goal. Chemotherapy options for HSA include the following:

1. AC - This protocol includes Adriamycin (generic name doxorubicin) which is given intravenously every 3 weeks for 4 treatments, and Cytoxan (generic name cyclophosphamide) which is given orally 10 days after each IV treatment. Adverse effects are uncommon but can include gastrointestinal effects (vomiting, decreased appetite, and diarrhea) and bone marrow suppression (decreased white blood cells). Also, Adriamycin rarely can cause toxicity to the heart muscle after multiple doses, therefore we recommend monitoring the heart function with ultrasound prior to the 1st and 3rd treatments. The estimate for this protocol is approximately $1200-1500.

2. VAC - This protocol includes the above plus vincristine which is given intravenously on days 8 and 15 of the 21 day cycle. Possible adverse effects are the same as those listed above. The addition of an extra drug increases the chance of problems a bit, but still VAC is well tolerated by many dogs. For pet owner's who want the most aggressive treatment for their pet, I recommend this protocol. The estimate is approximately $2500-3000.

Prognosis
The prognosis for dogs with HSA is poor. Even with the most aggressive treatment, eventually animals get sick from metastasis to abdominal organs or lungs. They often have recurrence of bleeding which leads to weakness and collapse. Sudden death can occur, but usually euthanasia is determined to be the most humane option prior to that point. The average survival for dogs with splenic HSA treated with surgery and chemotherapy is about 6 months. For those treated with surgery alone, it is about 3 months. If metastasis is present at the time of diagnosis, the average survival is 3 months with chemotherapy treatment and less than 6 weeks without chemotherapy treatment. Some cutaneous HSA tumors are less aggressive, but subcutaneous tumors have a prognosis similar to those in the spleen.