Companion Animal Welfare

Cat Injection Site Sarcoma Welfare

Injection site sarcomas are aggressive tumours associated with subcutaneous injections in cats. Prevention and early detection improve outcomes.

Key Facts

Injection site sarcomas affect approximately 1-4 cats per 10,000 vaccinations
Tumours develop at previous injection sites months to years later
Adjuvanted vaccines are associated with higher risk than non-adjuvanted
Wide surgical excision is the primary treatment but recurrence is common
Distal limb injection sites allow amputation if needed

Welfare Considerations

Injection site sarcomas are locally invasive and frequently recur after surgery. Affected cats face multiple surgeries, chemotherapy, and ultimately progressive disease. Prevention through careful injection site selection (limbs rather than scruff), use of non-adjuvanted vaccines where available, and prompt investigation of any post-injection swellings improves outcomes.

What You Can Do

Ask your vet about non-adjuvanted vaccines for your cat
Monitor injection sites and report any persistent lumps after 4 weeks
Ensure vaccinations are recorded by site for future reference
Support research into injection site sarcoma prevention and treatment