Injection Site Sarcoma Flashcards
Which injections are most commonly assoc. w/injection site sarcomas?
Rabies and FeLV
Why are vaccine injections more likely to cause sarcomas than other injection?
They elicit an immune response
What is the difference between an injection site sarcoma and a standard soft tissue sarcoma?
More invasive and more likely to recur after excision
Where are rabies vaccines administered?
Right hind (as distal as possible)
Where are FeLV vaccines administered?
Left hind (as distal as possible)
What masses should be biopsied?
Growth for 1+ month, >2cm size, present 3mo after vax
What margins do you want for surgical excision of an injection site sarcoma?
5cm + 2 fascial planes deep
What is the MST for an injection site sarcoma only treated with surgery?
1-1.5 years
What is the MST for an injection site sarcoma treated with radiation before/after surgery?
2 years
What chemotherapy do you use to treat an injection site sarcoma?
Doxorubicin
What is the biologic behavior of an injection site sarcoma?
Locally invasive w/tendrils or “fingerlike projections”
How often does an injection site sarcoma occur with a vaccine injection?
1 in 10k
How do you surgically treat a very distal injection site sarcoma?
Limb amputation
How can you accurately diagnose an injection site sarcoma?
Biopsy
How do injections site sarcomas compare to naturally occurring sarcomas histopathologically?
More necrosis, inflammation, and mitotic figures
Why is a CT or MRI helpful for surgical planning of an injection site sarcoma?
Tumor is often several times larger than what is externally visible
How soon after conservative surgery will an injection site sarcoma recurr?
2mo
How soon after radical surgery performed by referral surgeons will an injection site sarcoma recurr?
9mo
How soon after clean/complete histopathological surgical margins are obtained will an injection site sarcoma recurr?
16mo
What is the purpose of adjuvant treatment of injection site sarcomas?
Prolong time before recurrence
Which chemotherapy agent has up to 50% response rate in cats with macroscopic injection site sarcomas?
Doxorubicin
Where are FVRCP vaccines meant to be given?
R shoulder
