Hemangiosarcoma is a common cancer of middle-aged to older dogs that targets the spleen in 50% of those affected. In fact, it's the most common tumor of this organ. Less commonly, this cancer can manifest as tumors of the heart, lining of the heart (pericardium), skin, and the tissues underlying the skin. Other sites include the lungs, kidneys, mouth, muscle, bone, bladder, and uterus.

Like many aggressive cancers, hemangiosarcoma tumors can also metastasize to other organs.

Because this disease arises from the lining of the blood vessels, these tumors have a propensity to invade the vessels themselves. Eventually, most of these tumors will rupture and bleed, leading to death through severe blood loss in a significant percentage of afflicted dogs.

As some breeds are overrepresented, a genetic origin for this disease can be inferred, though the exact method of inheritance remains unknown. Interestingly, males seem to be slightly predisposed to hemangiosarcoma.

Though it's impossible to pinpoint the exact cause of this cancer, a combination of genetic and environmental factors is assumed. In pets who suffer the skin (cutaneous) version, exposure to sunlight is considered a significant risk factor.Unfortunately, the prognosis for most hemangiosarcoma patients is poor. Median survival times, even with aggressive treatment, tend to reach approximately only half a year's time.

Symptoms and Identification

Unless identified early through abdominal palpation, X-rays, or ultrasound, dogs with hemangiosarcoma of the internal organs will typically suffer bleeding when the tumor(s) rupture. This can present as weakness, collapse, difficulty breathing, or even sudden death.

Basic diagnostic testing is always recommended to help determine the extent of the disease and assist in identification of affected organs. More sophisticated options may be available depending on the invasiveness of the disease and availability of the diagnostic equipment.

  • Physical examination

  • Complete blood count (CBC)

  • Blood biochemistry panel

  • Urinalysis

  • Chest and abdominal X-rays

  • Abdominal ultrasound

  • Echocardiogram (heart ultrasound)

  • CT scans of the potentially affected organs

Affected Breeds

Though hemangiosarcoma can affect any breed, German Shepherds, Golden Retrievers, and Labrador Retrievers are known to be predisposed.


The most commonly applied treatment for hemangiosarcoma of the spleen -- if any is attempted -- involves the surgical removal of the entire spleen (splenectomy). Unfortunately, survival times for surgery of splenic hemangiosarcoma via splenectomy are only 2-3 months.

Chemotherapy is strongly recommended in all hemangiosarcoma cases to help delay the tumor's spread. If chemotherapy is employed as well (usually offered for pets who appear not to have preexisting evidence of other organ involvement), survival times for splenic tumor patients typically reach an average of 5-7 months.

Dogs with tumors of the heart are usually not treated surgically unless the tumor appears to affect the lining alone. These are sometimes approached by a procedure called a pericardectomy (removal of the heart's lining) to help keep the heart pumping normally. Chemotherapy is often recommended for these internal hemangiosarcoma patients, too.

It's recommended that patients with hemangiosarcoma of the skin be treated immediately through surgical removal of the offending tumor. Chemotherapy to help delay the spread of the cancer is usually offered to help prolong comfortable survival time.

Though chemotherapy in pets is designed to be humane and is well tolerated by our patients, many owners do not elect chemotherapy because of cost or as a result of the perception that poor quality of life may ensue.

In these cases, as well as when chemotherapy is ineffective or not well-tolerated, "metronomic" drug therapy is often employed. This means that a low dose of a variety of drugs will be used to help lengthen a pet's comfortable lifespan.

Veterinary Cost

As with many cancers that require surgery for diagnosis and treatment as well as chemotherapy for best effects, the cost of this disease can be quite steep. Though it's considered atypical, dogs who suffer hemangiosarcoma may even experience diagnosis and treatment costs that extend into the tens of thousands of dollars.

The cost of diagnosis and treatment depends on many factors, including geographic location (cost of living), standard of care (lower vs. higher standards of veterinary care), whether specialty hospitals are employed (higher quality equipment, certified personnel, and board-certification for veterinarians specialized in the fields of surgery and oncology).

Depending on the location of the tumor, definitive diagnosis may typically cost anywhere from $500 (for a small skin tumor) to $5,000 (should a tumor require immediate life-saving treatment in an emergency facility or treatment in a specialty hospital.

Treatment of the tumor post-operatively can be very expensive as well. Whether standard chemotherapy or metronomic therapy is employed, the high price of these drugs and the close monitoring these drugs entail means caretakers can rack up bills totaling anywhere between $500 to $3,000 per month post diagnosis and surgery.

Many owners elect not to treat their pets due to cost, perception of their pets' suffering, or because of a poor long-term prognosis.


There is no known method for the prevention of internal hemangiosarcoma.

For cutaneous (skin) hemangiosarcoma, however, prevention includes aversion to ultraviolet radiation or application of a pet-appropriate sunscreen to thinly haired areas of the body. This is especially recommended for light-haired dogs of predisposed breeds.


Hammer AS, Couto CG, Filppi J, et.al. Efficacy and toxicity of VAC chemotherapy (vincristine, doxorubicin, and cyclophosphamide) in dogs with hemangiosarcoma. J Vet Intern Med ;1991;5:160-166.

Sorenmo KU, Jeglum KA, Helfand SC. Chemotherapy of canine hemangiosarcoma with doxorubicin and cyclophosphamide. J Vet Intern Med 1993;7:370-376.

Ogilvie GK, Powers BE, Mallinckrodt CH, et.al. Surgery and doxorubicin in dogs with hemangiosarcoma. J Vet Intern Med 1996;10:379-384.