Hemangiosarcoma Cancer in Dogs and Cats
What is hemangiosarcoma?
Hemangiosarcoma (HSA) is a type of cancer that develops from the cells that normally form blood vessels (endothelial cells). As in many other types of cancer, the cause of hemangiosarcoma in most cases is unknown. However, we do know that sunlight can cause the cutaneous (skin) version of hemangiosarcoma. This form of the cancer is found on the skin of patients with pale/pink skin and thin fur who live in very sunny climates.
Hemangiosarcoma is more common in dogs than any other species and affects mostly middle-aged to older animals. Some breeds are more susceptible than other breeds to develop hemangiosarcoma internally such as:
- German Shepherds
- Golden Retrievers
- Labrador Retrievers
What are the symptoms of hemangiosarcoma?
Symptoms of hemangiosarcoma are variable and dependent on location in the body. In dogs and cats, the most common sites are the:
However, hemangiosarcoma can develop anywhere in the body.
In the skin, a red to purple colored superficial bump may be noted; this bump may bruise or bleed. Under the skin, a soft or firm swelling that may feel like a benign fatty tumor may be palpable. Symptoms for tumors that develop internally may be any combination of the following:
- Unexplained weight loss
- Bulging belly
- Decreased exercise/stamina
- Lethargy/sleeping more
- Decreased appetite
- Increased panting
- Pale gums
How is hemangiosarcoma diagnosed?
Typically, this cancer is diagnosed based on a biopsy that is reviewed by a veterinary pathology specialist. It is a cancer that is very difficult to diagnose using fine needle aspiration cytology. Abdominal ultrasound, x-rays, CT scan and surgery are all tools that are used to provide information about the extent of the disease in the patient’s body. There is not currently a perfect blood screening test for hemangiosarcoma.
What is the treatment for hemangiosarcoma?
Surgery is typically the ideal first treatment for hemangiosarcoma. For some types of hemangiosarcoma, it may be the only treatment option that is necessary. However, for many types of hemangiosarcoma, further treatment after surgery is recommended because of the potential for spread to other sites in the body (metastasis).
Chemotherapy is often recommended following surgery for tumors of the following sites: liver, spleen, beneath the skin/in the muscle (subcutaneous/intramuscular) and bone. Chemotherapy is usually recommended as the primary therapy for hemangiosarcoma of the heart as surgery in this location is very difficult to perform. Radiation therapy is sometimes used if surgery is unable to remove the tumor in its entirety from external surfaces. Whatever treatment is recommended, good quality of life is the most important goal for a pet’s team of veterinarians.
If hemangiosarcoma is diagnosed in your dog or cat, it is ideal to consult with an experienced veterinary professional such as a Board-certified Veterinary Oncologist. When such an individual recommends a personalized treatment plan, quality-of-life is expected to remain optimal because these veterinarians are experienced in managing cancer patients and only have your pet’s best interest in mind. This team might also include a surgeon, radiation oncologist, radiologist, internal medicine specialist, etc.
What is the prognosis for pets with hemangiosarcoma?
Prognosis depends on the site of the body that is affected and is quite variable:
- Sunlight-induced, superficial, skin hemangiosarcoma is often cured following surgery though other skin sites in the same patient may become affected by new cancer lesions that occur entirely independent of the first location. It is recommended for families with pets diagnosed with sunlight-induced skin cancer of any kind to practice future sun avoidance for the affected pet.
- In contrast, it is rare when patients with spleen hemangiosarcoma are cured following surgery to remove the spleen. Unfortunately, tumors that arise in that site are usually associated with metastasis (spread of tumor cells from primary site via the blood stream to new locations such as the lungs). This metastasis occurs even if there is no evidence of secondary tumor sites at the time of surgery. The average survival prognosis for patients with spleen hemangiosarcoma following surgery alone is approximately two months, with only 10% survival at one year. The average survival for dogs with spleen hemangiosarcoma treated with surgery and chemotherapy is improved at six to eight months and patients typically experience an excellent quality of life during treatment.
- The prognosis for other sites of hemangiosarcoma is quite variable. Consultation with a specialist who is board-certified by the American College of Veterinary Internal Medicine (such as a Veterinary Oncologist) can help you better understand your pet’s individual prognosis if he or she is diagnosed with hemangiosarcoma.
Can hemangiosarcoma be prevented?
The only means of prevention of this disease in the skin and eyelids is to avoid sun exposure in dogs with thin/fair hair and pale/pink skin (white pit bulls, white Boxer dogs, Whippets, etc.). There is no known preventive method for other types of hemangiosarcoma.
Gabrielle Angelo DVM, DACVIM (Oncology)