Dog Hemangiosarcoma

Lili Duda, VMD
Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"
My dog, a 13-year-old cocker spaniel, has developed a hemangiosarcoma in his right atrium, which has spread to his right ventricle. We are advised not to do surgery because the cancer is in his heart. In two days, we must decide whether or not we want chemotherapy. Are any of the new treatments in humans available for dogs? Are there any places for clinical tests for dogs? We are desperate in finding treatment for him.
Thanks for reading.

Lili Duda, VMD, Editor of the OncoLink Veterinary Oncology Section, responds:

Hemangiosarcoma is a very aggressive, high-grade soft tissue sarcoma. The prognosis is guarded, as these tumors are widely metastatic. Prognosis without treatment is 2-3 months on average (with MANY factors influencing this prognosis). Chemotherapy can typically double survival time; however, this is only 4-6 months. The traditional chemotherapy protocol includes doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan), with or without vincristine. A common cause of clinical problems with this tumor type is internal bleeding from the tumor. Sometimes the source of bleeding can be removed, which provides temporary palliation, but will not prevent the spread of the tumor in most cases. For example, if a tumor mass in the spleen is bleeding, the spleen can be removed. However, there may be multiple sites that are bleeding or have the potential to bleed, or the tumor may be located in an area that is not amenable to surgical removal.

Hemangiosarcomas that involve the left atrial appendage can be removed, but tumors involving the ventricles cannot. Sometimes decreased heart function is caused by blood accumulating within the pericardial sac that surrounds the heart, which causes compression on the heart and prevents normal filling and pumping. This can be managed by removing the pericardial sac. However, this treatment will not work if the decreased heart function is caused by tumor that is invading the heart muscle.

There are sometimes clinical trials available for a variety of veterinary tumors. Please see the Veterinary Cancer Society for information concerning current research trials for pets with cancer.