Dedham Veterinary Associates

DVA 326 Bridge Street * Dedham, MA 02026 * 781.326.2800

Feline Vaccine Associated Sarcoma

This is a tumor on the back of a cat

thought to be a fibrosarcoma related

to vaccination.

What is sarcoma?

Sarcoma is a type cancer that can occur in any animal, anywhere in the body. Cats can get a certain type of sarcoma called fibrosarcoma or vaccine associated sarcoma. Early discovery and removal with a wide surgical excision is the best treatment for this tumor. Since this tumor grows microscopic roots, it will sometimes grow back quickly after surgery if complete removal was not possible. In these cases radiation and chemotherapy may be helpful.

What causes feline vaccine associated sarcoma?

Experts have not completely discovered the reason cats get these tumors, but there is some connection between the tumors and injections, especially vaccine injections. Rabies and Feline Leukemia vaccines have been implicated the most, but there is some evidence that any vaccine, injection or trauma can elevate the risk of developing this cancer.

How would I know if my cat has sarcoma?

Vaccine associated sarcoma is usually discovered by cat owners as a firm lump under the skin. Any new lump, especially at the site of vaccination, should be examined by a veterinarian. We will show you at the time of vaccination where we are placing vaccines so that you may monitor your cat at home with special attention to the vaccine sites.

How can sarcoma be prevented?

Vaccines are very important for the prevention of serious and fatal diseases. However, vaccines should only be given when the risk of getting the disease out-weighs the risk of giving the vaccination. Cats that stay indoors and do not contact outdoor cats only need to be vaccinated for Rabies, two airborne respiratory viruses (Feline Viral Rhinotracheitis and Calicivirus) and a deadly airborne intestinal virus (Panleukopenia). Cats that go outdoors or live with outdoor cats should be vaccinated for Feline Leukemia in addition to the above diseases. Certain risk factors may make other vaccines necessary. Any unnecessary vaccines can raise the risk of sarcoma development.

What is Dedham Veterinary Associates doing to lower my cat’s risk of sarcoma?

There is a group of feline specialists called the American Academy of Feline Practitioners. This group of feline doctors has formed a task force called the Feline Vaccine Related Fibrosarcoma Task Force. They have made specific recommendations for vaccinating cats. At Dedham Veterinary Associates, we have adopted the recommendations from this special task force of feline doctors. We will only vaccinate your cat for a disease if a risk truly exists. We are currently using some new vaccines that have much lower to no risk for causing sarcoma. The older vaccines which were thought to be associated with fibrosarcoma contained an additional agent called an adjuvant. We have stopped using vaccinations with adjuvants in our feline patients. The Rabies vaccine type that we use in cats, called Purevax™ by Merial, must be given every year instead of every three years, but the greatly decreased risk of cancer makes it worthwhile. We are also adopting the Feline Fibrosarcoma Task Force’s recommendation to decrease the time interval of vaccination from once per year to once every three years for some vaccine types. Vaccination for Panleukopenia by injection is not needed every year for every cat. We can decrease vaccine injections by alternating an intra-nasal vaccine for the two respiratory viruses with the injectable non-adjuvenated vaccine for the respiratory viruses. This means that in some years your cat will get nose and eye drops instead of an injection. The intranasal vaccine can cause a little sneezing a few days later but in our opinion, sneezing is much better than cancer. Geriatric cats or cats with certain medical conditions may be exempted from certain vaccines. Finally, we use specific vaccination sites for cats. Upper respiratory vaccinations are placed under the skin as far as possible down on the right front limb. Rabies vaccinations are placed under the skin as far as possible down on the right rear limb. Feline Leukemia vaccinations are placed under the skin as far down as possible on the left rear limb. We place vaccinations in these places so that you can monitor your cat for any lumps or bumps at the vaccination sites that may be precursors to cancer. Again, we feel vaccinations are an extremely important part of your cat’s health care, and we recommend that your cat have them based on his or her individual risk for common feline diseases.

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