Heart Cancer in Dogs

Hemangiosarcoma is a malignant tumour that affects dogs of middle and older ages. It is relatively common and it mainly develops in medium to larger size breeds such as Golden Retrievers and German Shepherds, however it can also occurs in other breeds. The tumour originates from cells that line the blood vessels and it easily spreads to many organs including heart, liver, spleen, and skin. Hemangiosarcoma is aggressive, insidious, and clinical symptoms are more likely to show only in the later stages; these include weakness and bleeding (usually nose bleeding) that often can be confused with another type of blood disorder called immune mediated hemolytic anemia. Abnormal growth can occur in different parts of the heart, including the pericardium, heart base, or the myocardium. Heart tumors are not common in dogs. When they do occur, they typically affect middle-aged to older dogs (7-15 years) and there is some evidence that German Shepherds and Golden Retrievers may be at increased risk for developing this type of cancer. It's best to leave these issues to a specialist, specifically a veterinary oncologist.

Symptoms can be hard to spot and often the dog will die without owners will catch any signs of the disease. This is because the tumour develops within internal organs, and in most of the cases during the early stages the rate of tumour growth is relatively slow. However there are some clinical symptoms and changes in the animal behavior that have been reported in dogs affected by Hemangiosarcoma.

• Weakness.
• Pale color of the gums and of internal eyelids.
• Difficulty to breath.
• Bleeding.
• Abdominal swelling and pain.
• Lump on the skin.

The causes of a dog suffering from Hemangiosarcoma are still unknown; the tumour is initiated within cells lining small blood vessels and then it spreads within internal organs or more superficially on the animal’s skin. It is possible that there is a genetic/hereditary cause for this type of tumour as it commonly affects big size dogs and specific breeds. Also Dermal Hemangiosarcoma is more likely to occur in short hair dogs that have been exposed to sunlight; it appears in the animal’s hairless body areas such as inner tight and belly. Currently we cannot attest which are the specific causes leading to the onset of the Hemangiosarcoma, however it is possible that a combination of genetic and environmental factors highly influences the development of this disease.

Types

Hemangiosarcoma can be found in any type of tissue nourished by blood vessels, thus almost anywhere in the body. The tumor is classified according to the site of its onset and referred as Dermal, Subcutaneous and Visceral Hemangiosarcoma.

• Dermal Hemangiosarcoma: This is the less invasive and less likely to spread to other parts of the body. Dermal Hemangiosarcoma is easy to remove surgically and it has a high rate of complete remittance.
• Subcutaneous Hemangiosarcoma: It is more invasive than the Dermal one, as it develops underneath the skin and it is more likely to spread to internal organs.
• Visceral Hemangiosarcoma: This is by far the most insidious and difficult to spot, it mainly develops in the heart, the liver and the spleen. They are all life-threatening as they always lead to severe internal bleeding.

Hemangiosarcoma, especially at the beginning, is barely detectable in dogs and in most of the cases a physical examination cannot be conclusive or sufficient to determine the presence of the tumour. For its proper diagnose, X-rays, ultrasounds and a tissue biopsy are the most reliable tests for a suspected mass. In some cases analysis of the dog’s blood sample could reveal the presence of abnormal proteins or low levels of circulating red blood cells; this is very likely to be a sign of internal bleeding deriving from the tumour’s rupture.

When a Visceral or Subcutaneous Hemangiosarcoma is suspected pet’s owners could be of a great help in the diagnosis by taking a sample of the animal’s internal fluids either from the abdomen or from the chest. The presence of blood in the fluid can further confirm the presence of the tumour. Additionally pet owners are invited to carefully observe and evaluate for any changes in the dog’s personality and habits, especially to its vital functions such as eating and breathing, physical performances, and also physical signs like bleeding, gums and internal eyelids color and abdominal swelling.

Medical tests required for a conclusive diagnosis include:

• Abdominal or chest X-ray and/or ultrasounds
• Cardiac ultrasound
• Electrocardiogram
• Blood tests including total count of red and platelet cells and serum proteins
• Surgical biopsy of suspected mass

There are not many options to treat Hemangiosarcoma mainly because the disease is very difficult to diagnose early at the onset and also because similarly to other type of tumours the available therapies are very unspecific and they are associated with many side effects.

The surgical remove of the internal tumour is probably the best option available, although in most of the case it does not represent a completely cure but it can ameliorate the dog’s life as it decreases the risk of internal bleeding due to the tumour rupture. Surgical procedures especially cardiac and liver surgeries are very risky and complicated as those are vital organs and often the mass is highly interwoven within other tissues. Additionally a complete tumour eradication is almost impossible to achieve, as often at the time of the surgery, the tumour has already spread within the body and this implies further long-term treatments such as chemotherapy or ultrasounds.

Chemotherapy is another possible option; it consists in the intravenous administration of a drug that blocks the replication of rapidly dividing cells such as tumour cells, thus preventing their growth. On the bad side short-term side effects are generally very severe as chemotherapy drugs cannot discriminate between tumour cells and other type of cells in the body. The most common side effects include nausea, decrease in appetite, weakness, hair loss and in some cases death.

Natural remedies such as herbs, vitamins and holistic approaches have recently gained public attention to treat this type of disease, although at the moment there are no scientific evidences for successful treatments of the tumour.

The surgical treatment of Hemangiosarcoma requires a follow-up time during which the animal is strictly observed and monitored with medical tests and analysis to ensure the best recovery and overall his well-being. Surgeries are often followed by chemotherapy or ultrasounds that require a routine schedule. Moreover chemotherapy is associated with blood cell analysis in order to control the effect of the drug on the bone marrow. If the dog shows some changes in eating habits, his diet needs to be adjusted accordingly or it is necessary to provide supplements and supportive medications such as intravenous fluids.

The recovery time for dogs affected by Hemangiosarcoma is extremely variable; and dogs diagnosed with internal Hemangiosarcoma die within less than a year from the diagnosis. A better chance of survival is for dogs affected by Subcutaneous and Dermal Hemangiosarcoma that are less likely to spread and often have a complete remission following surgical removal of the tumor.