Hemangiosarcoma in Dogs

The following 2 articles appeared in “Fully Vetted – A Veterinary Blog for Pet Lovers and Pet Voyeurs”

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I recently euthanized a dog that greeted me at his front door with a goofy grin on his face and a wagging tail. This type of appointment just breaks my heart, yet I was fully supportive of the owner’s decision to euthanize. Why? Because the dog had been diagnosed with hemangiosarcoma of the heart. Faced with this disease, I would much rather euthanize a week “too early” than a day “too late”. Read on to find out why.

What is hemangiosarcoma?

Hemangiosarcoma (HSA) is an aggressive, malignant cancer of the blood vessels that often grows as a mass in the spleen, liver, or heart, but can also be found in other parts in the body. Animals usually present to their veterinarian for sudden collapse due to internal bleeding from the mass. In most cases, by the time the animal is showing clinical signs, the cancer has spread to other areas of the body, such as the lungs. HSA can be diagnosed with X-rays, ultrasound, aspiration of abnormal fluid accumulations, and biopsy of the mass via exploratory surgery.

How is it treated?

Unfortunately, while there are treatment options available, there are no cures for this disease. Surgery may be an effective option for removing the primary tumor and temporarily stopping bleeding, but it is not capable of removing all of the metastatic disease, which is usually microscopic at the time of diagnosis. Chemotherapy is often used in conjunction with surgery to help combat the cancer cells that have spread throughout the body.

What symptoms can present as the disease progresses?

Early Stages

  • loss of appetite
  • weight loss
  • lethargy
  • exercise intolerance
  • vomiting/diarrhea
  • pale gums
  • possible distended abdomen
  • possible increased respiratory rate and effort

Late Stages

  • persistent early stages
  • reclusive behavior
  • distended abdomen
  • dull mentation
  • difficulty breathing
  • panting, gasping for breath
  • possible black, tarry stool
  • sudden collapse
  • unable to rise

Crisis – Immediate veterinary assistance needed regardless of the disease

  • Difficulty breathing
  • Prolonged seizures
  • Uncontrollable vomiting/diarrhea
  • Sudden collapse
  • Profuse bleeding — internal or external
  • Crying/whining from pain*

*It should be noted that most animals will instinctually hide their pain. Vocalization of any sort that is out of the ordinary for your pet may indicate that their pain and anxiety has become too much for them to bear. If your pet vocalizes due to pain or anxiety, please consult with your tending veterinarian immediately.

What is the prognosis for hemangiosarcoma (HSA)?

A diagnosis of HSA almost always carries a poor prognosis, the only exception being HSA originating from the skin with no internal involvement. If treatment is not an option, euthanasia should be considered to prevent suffering from internal bleeding. Surgery alone to remove the primary tumor carries a median survival time of 1-4 months, while chemotherapy in addition to surgery carries a median survival time of 6-8 months.

Even with surgery and chemotherapy, the disease will progress and the cancer cells with continue to metastasize, creating masses throughout the entire body. Hemorrhages may occur from each cancer site, which may cause transient weakness until the bleeding stops. If the bleeding does not stop, the patient will start showing signs of shock and collapse. To save both the dog and owner from the horrors of this experience, I always prefer to euthanize sooner rather than later when faced with a diagnosis of hemangiosarcoma.

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Dr. Jennifer Coates

More on Hemangiosarcoma


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(4) comments

I received a few questions in response to last week’s post on hemangiosarcoma in dogs. I thought I’d address them all together here.

1. Is there any (non-invasive) way to find hemangiosarcoma before there are clinical signs? Is there anything subtle that might be a clue?

Hemangiosarcoma is difficult to diagnose before clinical signs develop. The best, practical option is to bring older dogs in to see the veterinarian twice yearly for wellness checks. A physical exam and routine lab work can point to problems before symptoms arise. An ultrasound is the most sensitive tool for picking up small tumors in the abdomen or heart, but I wouldn’t recommend this as a screening test (i.e., for use on apparently healthy animals). A blood test is available for hemangiosarcoma, but again, it is not recommended for use on dogs with no clinical signs. Rather, it can play a role in differentiating this disease from others that have similar symptoms.

The earliest, most subtle sign associated with hemangiosarcoma in dogs is intermittent lethargy due to small bleeds that stop on their own. Unfortunately, almost all dogs have this symptom at some point in their lives, so it’s not too discriminating.

2. Is the course of hemangiosarcoma different in cats?

I’ve never diagnosed hemangiosarcoma in a cat, so I had to do a little research. Here are some quotes from a fascinating (at least to me) paper that was published in 2007 in the Journal of the American Veterinary Medical Association.

Feline hemangiosarcoma is a rare neoplasm of cats and was diagnosed in only 18 of 3,145 necropsies performed over an 11-year period – as in prior reports, no breed or sex predilection was detected in the present study, and most cats were middle-aged to older animals at the time of initial diagnosis.

Although the specific etiology of hemangiosarcoma is not well understood, the prevalence of cutaneous lesions on the head (including conjunctiva), muzzle, and ears make exposure to UV radiation and local pigmentation characteristics potential predisposing factors.

Surgical excision was the primary treatment modality used for cutaneous and subcutaneous hemangiosarcoma in the present study…

Results of the present study indicated that in cats cutaneous (involving the skin) and subcutaneous (involving the tissues under the skin) hemangiosarcoma may occur more commonly than visceral (involving a large organ in the abdomen or chest) hemangiosarcoma. Similar to canine hemangiosarcomas, feline subcutaneous hemangiosarcomas are more likely to be incompletely excised, recur locally, and have more aggressive biological behavior than cutaneous masses. Thus, subcutaneous hemangiosarcoma may warrant more aggressive surgical excision, multimodality therapy (a combination of surgery, chemotherapy, and/or radiation), and a more guarded prognosis – as in dogs, visceral hemangiosarcoma in cats warrants a poor to grave prognosis despite therapeutic interventions. As additional cats with hemangiosarcoma are treated with adjunctive therapy, more detailed information regarding the best treatment options and response to specific therapy will hopefully become available.

3. Is this an inherited disease?

We don’t have any specific evidence that heredity plays a role in most cases of canine hemangiosarcoma. However, the fact that the disease has a higher incidence in some breeds (e.g., boxers, doberman pinschers, German shepherd dogs, golden retrievers, Labrador retrievers, pointers, and schnauzers) indicates that genetics could be one of several factors that combine to determine which dogs are affected and which remain free of this devastating disease.

Dr. Jennifer Coates

Petmd Blog

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