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Injection-site sarcomas in cats

Srivastav A, Kass PH, McGill LD, Farver TB and Kent MS. Comparative vaccine-specific and other injectable-specific risks of injection-site sarcomas in cats. J Am Vet Med Assoc. 2012; 241: 595-602.
Injection site sarcomas are malignant tumors that have been associated with vaccination sites. However, the factors associated with injection site tumors remain largely unknown or controversial at best. This study examined the associations between vaccine types and other injectable drugs with the subsequent development of injection site sarcomas in cats. For this study, pathologic samples from 181 cats with soft tissue sarcomas (STS) at injection sites were compared with 96 cats with tumors at non-injection sites and 159 cats with other tumor types. By examining both anatomic and temporal associations, it was found that association of STS with injections of long-acting steroids was higher in cats with tumors at injection sites (interscapular) than cats without tumors at these sites. It was also found that recombinant vaccines were less likely to have been used at injection site sarcomas than inactivated vaccines. Overall, the propensity for tumors to arise at injection sites was small. [MK]

See also: Wilcock B, Wilcock A and Bottoms K. Feline postvaccinal sarcoma: 20 years later. Can Vet J. 2012; 53: 430-4. [free full text article]