Feline Injection Site Sarcoma (FISS), which rarely occurs at injection sites in cats, worries the families of our lovely friends. However, this condition, which can cause aggressive tumors such as fibrosarcoma, can be prevented with the right vaccination techniques. Veterinarian Uğur Selin Çelikten made important statements to inform pet owners who have recently been wondering whether to vaccinate or not about FISS.
Risks and Things to Know
“Cancers that occur at the injection site in cats, especially fibrosarcoma types, are known as “Feline Injection Site Sarcoma (FISS)” in the veterinary field and are considered a rare but serious side effect of vaccination,” Çelikten said.
“These tumors are more aggressive than other fibrosarcoma-type cancers and the rate of metastasis, or spreading to other parts of the body, varies between 10-28%. Cancers that form at the injection site are not as prone to spreading to other parts of the body as other sarcomas. However, they can spread widely and deeply in the area where they are located. Although it is not fully understood why vaccine site cancers (FISS) occur, experts agree that chronic inflammation at the injection site may be a trigger for malignant cellular transformation,” he said.
Çelikten emphasized that despite these risks, vaccination provides basic protection against many diseases that can be fatal and is indispensable for the health of cats.
What Should Be Done to Reduce the Risk of FISS?
Veterinarian Uğur Selin Çelikten listed the precautions that should be taken to minimize the risk of FISS as follows:
- Alternative Vaccination Methods: Alternatively, intranasal vaccines can be used. If there are vaccines that can be administered subcutaneously or intramuscularly, other than those that can be administered into the nose, these can also be preferred.
- Correct Application Technique: Injections should be made in the lower legs or tail, where surgical intervention can be easily applied. Because when the cancer formed at the vaccination site is removed; if there are tumor cells left, they can grow back very aggressively. Therefore, when this type of cancer forms, the lower legs are amputated (partially cut) and the body is radically cleansed of this tumor.
- Applied Region: Cancers that occur at the vaccination site are most commonly seen between the two shoulder blades, the rib cage, and the back leg. It is important to avoid these areas as vaccination sites. Since it is a type of cancer that progresses deeply, it is not possible to remove cancer deeply from the rib cage or between the two shoulder blades.
- Vaccine Selection: Care should be taken to select live and unadjuvanted vaccines whenever possible. It may be a logical option to choose unadjuvanted vaccines when they are available and effective. There is still no consensus on the rate of sarcoma, or regional cancer, of adjuvanted vaccines compared to unadjuvanted vaccines. However, it is a fact that adjuvanted vaccines cause more inflammation. Therefore, if there is no difference in effectiveness, unadjuvanted vaccines should be selected.
- Monitoring According to the “3-2-1” Rule: If, even after 3 months have passed since the vaccination, your cute little friend still has masses that are larger than 2 cm in diameter or that grow within 1 month, he/she must undergo surgery and the removed tissues must be taken for histopathological examination.”
Reminding that feline injection site sarcoma is a rare condition, Çelikten said, “Studies report that the incidence of these tumors is one in every 1000-10.000 injections. With a simple calculation, if we consider that a cat will receive an average of 45 vaccinations throughout its life, the probability of this cancer developing is quite low. With the protective measures implemented today, it is expected that this rate will decrease even further. The development of tumors in the vaccination site can occur within a period ranging from two months to 10 years. However, the vast majority of cases occur within four years after the injection.”
Should I Vaccinate My Cat?
Çelikten said that many parents are worried about whether they should vaccinate their cats.
“We should definitely say yes to vaccination! Vaccines are vital to prevent many diseases that can be fatal in cats. As veterinarians, we create a vaccination program that suits the individual needs of each cat and apply it with the right techniques. Consulting their veterinarians on this issue is the most important step in protecting their health,” he said.
Uğur Selin Çelikten added that this rare complication can be prevented with careful monitoring and correct application techniques after vaccination.
Treatment and Early Diagnosis Saves Lives
Çelikten, who emphasized that early diagnosis plays a major role in the treatment of FISS and that a multidisciplinary approach is necessary in the treatment process, gave the following important information:
“Histopathological examination is essential for definitive diagnosis. Efforts should be made to leave no cancer cells in the area during surgical intervention. Radiotherapy and chemotherapy can be used in addition to surgical intervention. Immunotherapy can be considered as an alternative supportive treatment.
Remember, vaccinations are essential to your pet's health, but knowing about these rare complications can save their lives.
Don't neglect regular veterinary check-ups for your pet's health. Be informed about possible side effects after vaccination and stay in touch with your veterinarian to protect the health of your friends."
