Vaccine Associated Sarcoma

Vaccine associated sarcoma (VAS) is a type of tumor that develops over time as a result of certain vaccines. The disease is also known as feline vaccine associated sarcoma, though rarely vaccine associated sarcoma affects dogs, ferrets and other animals.

Vaccine associated sarcoma can appear as soon as three months after a vaccine is given, but can take up to 11 years to appear.

Vaccine Associated Sarcoma Statistics

  • Vaccine associated sarcoma occurs in approximately 20 out of 100,000 vaccinated cats.
  • Vaccine associated sarcoma usually affects cats age 6.4 and over, though younger cats can also be affected.
  • Vaccine associated sarcoma is most often associated with rabies vaccines and feline leukemia vaccines, though it has also been associated with other vaccines.

Symptoms of Vaccine Associated Sarcoma

Vaccine associated sarcoma is most often seen as a mass forming on the skin and under the skin. The mass will grow rapidly and will contain fluid.

A biopsy from a veterinarian is necessary for an accurate vaccine associated sarcoma diagnosis, so if your pet exhibits symptoms of VAS, schedule a visit to the veterinarian as soon as possible.

Treatment: The Earlier the Better

The only effective treatment for vaccine associated sarcoma in dogs and cats is surgery. The mass needs to be removed as quickly as possible. The sooner the mass is removed, the better the animal’s chance for survival.

Generally, a surgery to remove a mass will include removal of a certain amount of tissue around the mass as well, just to ensure that all of the mass is removed. In some cases, pets may receive chemotherapy or radiation therapy along with surgery during the treatment process.

VAS Prevention and Precautions

Because vaccine associated sarcoma is associated with vaccination, it is important not to over-vaccinate your cat. New research has been done that indicates that not all vaccines need to be given every year. “Boosters,” or re-vaccinations, can be done every three years for some diseases.

Cats really only need to be vaccinated for diseases that they are at risk for developing. Indoor cats are at risk for far fewer diseases than outdoor cats. Outdoor cats come into contact with other cats, sometimes strays with many diseases, and are exposed to the elements.

Talk to your veterinarian about which vaccines are necessary for your pet. Your veterinarian should take into consideration:

  • whether your pet is an indoor or outdoor pet
  • your pet’s age
  • your pet’s environment
  • your pet’s overall health
  • your pet’s susceptibility to disease.

Your vet can also discuss how often to vaccinate your pet. Every year it may be necessary for certain vaccines to be given, while others can be given every three years. Whatever you and your vet decide, do not eliminate yearly check-ups with your vet. These appointments are important for your pet and can be a chance for your vet to catch health problems or diseases early on. This can help with treatment and can help to provide a better prognosis for your pet.