Companion Animal Welfare

Cat Feline Injection Site Sarcoma Welfare

Injection site sarcomas are aggressive tumours at vaccination and injection sites in cats requiring early recognition and wide surgical excision for best outcomes.

Key Facts

Injection site sarcomas affect approximately 1-4 cats per 10,000 vaccinations
They are caused by inflammatory reactions to adjuvants in some vaccine formulations
Tumours develop months to years after injection with aggressive local invasion
Wide surgical excision of 3-5cm margins is required for tumour-free resection
Adjuvant-free vaccine formulations may reduce sarcoma risk

Welfare Considerations

Injection site sarcomas cause significant welfare harm through aggressive tumour invasion and the extensive surgery required for treatment. Early detection of any lump at injection sites enables prompt assessment and wide surgical excision that offers the best welfare outcome.

What You Can Do

Check the area between your cat's shoulder blades monthly for lumps
Report any injection site lump persisting beyond 4 weeks to your vet for assessment
Ask your vet about adjuvant-free vaccine options that may reduce sarcoma risk