Canine hemangiosarcoma, one of the five most commonly diagnosed types, offers few warnings. Many of these fragile, blood-filled tumors are not discovered until they burst. At this point, emergency surgery is the only treatment option.
What is it?
As the name suggests, these tumors develop from cells that line blood vessels. Because the body is littered with blood vessels, hemangiosarcoma can appear anywhere. This means that in about 50 percent of cases it affects the spleen, followed by the liver, heart or, rarely, the skin. This aggressive cancer (which is very similar to the relatively rare human angiosarcoma) most commonly affects middle-aged older dogs, with slight preference for men.
For the most part, it is not known why hemangiosarcoma develops, although for those who develop on or under the skin, excessive sun exposure in thin-haired areas such as the abdomen, inner thighs, and eyelids is believed to be the culprit.
Signs and symptoms.
A tumor on or under the skin appears as a dark red / purple bump that can cause bruising or bleeding. However, early signs of internal tumors can be as subtle as lethargy and pale gums.
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At first, a hemangiosarcoma slowly develops. As the tumor grows, the blood vessels that support it begin to leak, causing blood loss in the abdomen, and the symptoms become more severe: weight loss, decreased appetite, increased wheezing, weakness, cough, a bulging stomach.
The most common appearance that general practitioners see veterinarians is a dog who is suddenly weak, has a drooping abdomen, and pale mouth membranes. This is the result of a ruptured spleen mass causing intra-abdominal bleeding (bleeding in the abdomen). .
How is it diagnosed?
For suspicious masses of skin (those that are larger than a pea and / or that are more than a month old), fine needle aspiration is used to secure a sample. However, if an internal tumor is suspected, this method is much more difficult. Instead, the diagnosis usually includes blood tests, an ultrasound of the abdomen, x-rays, and a CT scan.
How is it treated?
Surgery and chemotherapy are the most common treatments, although hemangiosarcoma is likely to have metastasized at diagnosis. (One possible exception is hemangiosarcoma in or under the skin, which generally occurs earlier than one in the body.) The main goal of treatment is to slow or delay the spread of the tumor and prevent life-threatening bleeding. A cure or even remission is extremely unlikely at the moment.
A mass of spleen that ruptures must be operated on to remove the spleen. While surgery can be life-saving if the mass is a hemangiosarcoma, it has already metastasized microscopically. Since approximately 50 percent of the bleeding masses in the spleen can be benign, it is worth doing a splenectomy and pathological examination of the spleen, although this may only give the dog a few months more quality of life if it is found to be Mass is a hemangiosarcoma. Within three to four months, the dog will have multiple tumors in the lungs and other parts of the body.
A 2012 study at the University of Pennsylvania reported success with an extract of a medicinal mushroom, Coriolus versicolor, in extending the life of 15 golden retrievers with hemangiosarcoma. The mushroom contains a compound called polysaccharopeptide, or PSP, which some studies have shown to have both immune-boosting properties and anti-tumor effects. It has no side effects and is relatively inexpensive. (It has also been studied for use in human cancer patients, with positive results.) However, to date it has rarely been suggested or used by veterinary oncologists, probably due to a lack of research.
Researchers at the University of Minnesota College of Veterinary Medicine, led by Jaime Modiano, VMD, PhD, approach the disease from a different direction. The Shine On project is tracking 209 otherwise healthy dogs who have completed the third phase of the study to determine the reliability of the results of a novel blood test. With this test, the researchers assigned a risk to each dog.
It is currently estimated that a dog that tests negative hemangiosarcoma has a less than 1 percent chance of developing it over a six month period, while more than 90 percent of dogs with a positive test will need further evaluation.
As a preventive measure, dogs at high risk can receive eBAT, a genetically modified drug that was developed at the university in 2017. According to Daniel A. Vallera, inventor of the drug, “eBAT was developed to target tumors while minimizing damage to the immune system. … [It] was selected for this study because it can target the tumor and its vasculature at the same time. “In other words, it kills emerging cancer cells and inhibits the environment that needs them to grow.
Results so far show that the novel blood test can not only show the presence of hemangiosarcoma in otherwise healthy dogs with 90 percent accuracy, but can also predict when treatment will fail and the disease will return.
Are Certain Races Predisposed?
Golden Retrievers, German Shepherds, Portuguese Water Dogs, Boxers, and Skye Terriers are the breeds most commonly affected.