Due to the early spread of this tumor, chemotherapy is frequently recommended in addition to other treatments. The only exception to this is when the tumor is localized to the very uppermost layer of the skin. Then surgical removal of the tumor may be all that is required.
The most commonly used chemotherapy drug is doxorubicin. This drug is administered intravenously once every three weeks. Cats handle this drug well and the risk of serious side effects is low, between 5 to 10 percent. Potential side effects include gastrointestinal problems, including nausea, vomiting, diarrhea or loss of appetite, and a drop in the white blood cell count, leaving a pet susceptible to infection. If multiple treatments of this drug are given, cumulative side effects include heart problems. In order to prevent the cumulative side effects, the number of treatments is limited to six or less. In cats, a heart evaluation (ultrasound and EKG) is recommended prior to giving the drug and before the fifth and sixth treatment.
Other drugs that are used in the treatment of hemangiosarcoma are cyclophosphamide and ifosphamide. Cyclophosphamide is frequently given either with doxorubicin or immediately after. When ifosphamide is used, it is alternated with doxorubicin. Both of these drugs can cause gastrointestinal side effects and a drop in the white blood cell count. In addition, they can cause an irritation in the lining of the bladder causing blood in the urine and straining to urinate. If the drug irritates the bladder the signs will usually resolve in a few days to a few weeks.
Radiation therapy may be performed and involve the following: Full course radiation therapy. This type of radiation therapy is used when a tumor involving the skin or underlying tissues cannot be completely removed. In order for full course radiation to be effective, all visible evidence of the tumor must be removed first with surgery. In this situation, 16 to 19 treatments of radiation may be given over a four to six week period of time. The side effects include hair loss and redness and ulceration of the skin. These side effects are present only for a three to four week period of time and can be managed with medications.
Palliative radiation therapy. This type of radiation therapy can be used to control symptoms such as pain when the tumor cannot be entirely removed with surgery. It involves giving a few large doses of radiation therapy to the tumor over a two to three week period of time. Side effects are very few and is most commonly used when the tumor occurs in the bone.
Prognosis may vary. The recommended course of treatment and outcome depends upon the location of the tumor.
Hemangiosarcoma of the spleen is aggressive. The recommended treatment is surgery (to remove the spleen) and chemotherapy. If the only treatment is removal of the spleen, the survival time is short (between one to two months). If chemotherapy is given after surgery the survival time is improved and is about six months.
When the hemangiosarcoma is in the liver, the treatment recommendations and outcome are similar to that of the spleen.
When the hemangiosarcoma is in the heart, the recommended treatment is to remove the tumor if possible and follow-up with chemotherapy. With surgery alone, the survival time is less than four months. With chemotherapy, the survival time is extended to six months or more.
If the tumor occurs in only the upper layer of the skin the outcome is excellent. In that situation, the only required treatment is complete removal of the tumor with surgery. When the tumor involves the deeper layers of the skin or the underlying tissues, there is a greater potential for spread of the tumor to other organs. The recommended treatment is to remove the entire tumor with surgery and to follow-up with chemotherapy. If the entire tumor cannot be removed with surgery but is reduced to the level where the tumor cannot be felt, radiation therapy is recommended in addition to the surgery and chemotherapy. In this situation, survival times are between eight to 12 months with treatment.
Hemangiosarcoma of the bone is an aggressive tumor. The most common bones affected are the ribs, forelimbs and vertebrae. The recommended treatment is removal of the affected bone if possible followed by chemotherapy. In situations where the affected bone cannot be removed, palliative radiation therapy can be given to control pain. The survival time for hemangiosarcoma of the bone with treatment is around six months.
Seek veterinary attention promptly if your pet develops pale gums or signs of weakness or collapse. These may be symptoms of hemangiosarcoma or other potentially serious conditions.
Have any new lumps on your pet evaluated by your veterinarian. Hemangiosarcoma of the skin or underlying tissues can be difficult to distinguish from less serious skin tumors. Early detection may increase the possibility of successful treatment.
Restrict your cat's activity after surgery until suture removal. Monitor the incision for any signs of redness, swelling or discharge. Keep you pet from chewing or scratching at the incision.
If your cat receives chemotherapy monitor him for changes in appetite and activity. The most common side effects of chemotherapy are appetite loss, vomiting and/or diarrhea. Mild signs can frequently be managed at home with diet changes. Anti-nausea or anti-diarrhea medications can also be prescribed. Your veterinarian should be notified if the signs are severe or last longer than a few days. Rarely, your veterinarian may recommend hospitalization to prevent dehydration. Signs of infection include loss of appetite, fever and extreme tiredness. Infections in patients with low white blood counts are serious and require intravenous antibiotics.
Minimize your cat's exposure to the sun. Hemangiosarcoma of the skin can be caused by excessive exposure to the sun.