Vaccine Related Sarcomas

Vaccine Related Sarcomas

                        Vaccine related sarcomas are defined as soft tissue tumors often found near injection site. Incident rate is about 1 out of 10,000. These sarcomas are associated with Feline Leukemia and rabies vaccines, but may be genetic. Cats may receive multiple vaccinations over a lifetime with the same or varying agents. They may develop months or years after a vaccination and not be apparent until a subsequent vaccine has been given. Dull needles may even be a cause. As soon as a lump is discovered, immediate veterinary evaluation is crucial to determine if it is a sarcoma. Sarcomas are difficult to treat, with a poor prognosis. Smaller tumors and surrounding tissue are removed, followed by radiation and chemotherapy treatment. Larger tumors may also infect bone and have a higher mortality rate. Cats with prior reactions can be pretreated with antihistamines or corticosteriods. It is suggested to choose a different vaccine such as purvax for rabies which decreases the chance, or dividing up the vaccine fractions so only a single antigen is given at a time.