Heart Hemangiosarcoma in Cats and Dogs
What are heart hemangiosarcoma tumors?
Heart hemangiosarcoma is an aggressive, highly metastatic malignant tumor arising out of the lining of heart blood vessels
and accounts for approximately 40-60% of all heart tumors in dogs The heart is enclosed in a sac called the pericardium
and when the hemangiosarcoma bursts and begins to bleed (referred to as pericardial effusion), the blood fills up the sac
(referred to as cardiac tamponade) which then interferes with the heart's function.

What are the symptoms of hemangiosarcoma?        
Heart tumors can cause varied clinical symptoms depending on their size, location and whether they ruptured and caused
internal bleeding. The observed clinical symptoms are typically seen due to the obstruction of blood flow into or out of the
heart, interference with effective pumping of the blood and/or disruption of normal heart beat. The most common signs in
animals with heart tumors are fainting, shortness of breath, lack of appetite, weight loss and general weakness. Acute
death from tumor rupture with subsequent blood loss is a common consequence of heart hemangiosarcoma and sudden
death due to heart arrhythmia (irregular heart beat) may also occur.

How is the diagnosis made?
The diagnosis of heart tumors in the dog and cat is typically based on physical examination, clinical history, complete blood
count, serum biochemical profile, coagulation profile,
X-rays and echocardiographic studies. Abdominal and chest x-rays
are often performed to determine the extent of the disease and whether the tumor has
metastasized to other organs.
Electrocardiogram analysis (an instrument that records the electrical activity of the heart over time; commonly known as
EKG or ECG) evaluates the heart's function and may detect some abnormalities. Ultrasound of the heart
(echocardiography) has become a very valuable diagnostic tool for identifying heart tumors in cats and dogs. There is also
some evidence that increased levels of proteins called cardiac troponins in the blood may be indicative of heart
hemangiosarcoma. Fine-needle aspirate or biopsy may be obtained for diagnosis confirmation whenever technically

Does cancer cause pain in pets?
Pain is common in pets with cancer, with some tumors causing more pain than others. In addition to pain caused by the
actual tumors, pets will also experience pain associated with cancer treatments such as surgery, radiation therapy or
chemotherapy. Untreated pain decreases the pet's quality of life, and prolongs recovery from the illness, treatment or
injury. It is, therefore, essential that veterinary teams that are taking care of pets with cancer should also play a vital role in
educating pet owners about recognizing and managing pain in their pets. The best way to manage cancer pain in pets is to
prevent it, a term referred to as preemptive pain management. This strategy anticipates pain ahead of time and
administers pain medication before the pet actually experiences pain, thus ensuring the pet's maximum comfort.

To learn more about which tumors are likely to cause a lot of pain, how to recognize pain in pets with cancer and what
cancer pain management options are available for your pet, please visit the
Cancer Pain Management section.

How important is nutritional support for pets with cancer?
Cancer cachexia (a term referring to progressive severe weight loss) is frequently observed in pets with cancer. Pets with
cancer lose weight partly because of lack of appetite and partly because of cancer-induced altered metabolism. Some of
the causes for decreased appetite are related to the cancer itself (for example, tumors may physically interfere with food
chewing, swallowing, and digestion process) and some may be related to the side effects of cancer treatment (for example,
some chemotherapy drugs cause nausea and vomiting, and radiation therapy can cause mouth inflammation).

Proper nutrition while undergoing cancer treatment is essential to maintain your pet's strength, improve survival times,
quality of life and maximize response to therapy. Adequate nutritional support was shown to decrease the duration of
hospitalization, reduce post-surgery complications and enhance the healing process. Additionally, pets with cancer need to
be fed diets specifically designed to provide maximum benefit and nutritional support for the patient. To learn more, please
visit the
Cancer Nutrition section.

What are the treatment options for heart hemangiosarcomas in cats and dogs?
The two main treatment options for heart hemangiosarcomas are surgery and/or chemotherapy. Surgery may be possible
only in a small number of pets, usually those with a single heart mass.  In order to control the metastastic spread,
veterinarians have used chemotherapy protocols that include drugs such as doxorubicin alone, doxorubicin +
cyclophosphamide, or doxorubicin + cyclophosphamide + vincristine. Unfortunately, both of these treatments are not very
effective and generally improve the pets' survival by only a few months.

Are there any clinical trials investigating new treatments for heart hemangiosarcoma in cats and dogs?
There are no available clinical trials investigating new treatments specifically for heart hemangiosarcomas in pets.
However, there are several clinical trials available for cats and dogs with any tumor type for which your pet may qualify. To
learn more these trials (which are partially or fully funded by the institutions), please visit the
Dog Clinical Trials (any tumor
type) or Cat Clinical Trials (any tumor type) section.  

To learn more about veterinary clinical trials in general, please visit the
Pet Clinical Trials section.

What is the prognosis for cats and dogs with heart hemangiosarcoma?
The prognosis for primary cardiac tumors is generally poor. Most pets respond poorly to medical treatment and the
reported average survival times of dogs with heart hemangiosarcoma treated with surgery alone range from 46 days to 5
months. Adding chemotherapy to the surgical treatment increases the average survival time to 164 days.     

Where do I find a qualified veterinary oncologist?
To locate a qualified veterinary oncologist worldwide who can discuss with you appropriate cancer treatment plan for your
pet's cancer condition, please visit the "
Locate a veterinary oncologist" section.  

Additional online resources about heart hemangiosarcoma

Scientific articles of interest

  • 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.
Comprehensive guide to cancer diagnosis and treatment in cats and dogs
© 2007 Pet Cancer Center. ALL RIGHTS RESERVED.
Last updated 2/19/2017