Feline injection site sarcoma — the very last words you want to hear combined with your cat’s name. Chances are your cat has just been handed a death sentence, and cost for palliative care, just to keep them from suffering, can run into thousands of dollars.
I hate to start this off on such a negative note, but it can’t be avoided. Feline injection site sarcoma, or FISS, isn’t talked about enough, and even among veterinarians, information is lacking. Somewhere between one in 1000 and one in 10000 cats will receive this devastating diagnosis. That is a huge spread, and so far — at least in 2023 — no one has narrowed it down. And honestly, numbers aren’t that important when that one is the most important cat in your life — your own.
Why do I care about this so much? Because FISS can hit a disproportionate number of therapy cats. As you have probably guessed, one of the most common ways that a cat develops FISS is through vaccination, usually FeLV or rabies vaccines. And therapy cats are required by their organization to keep up on their vaccines. We cannot skip them if we want to keep working. And recently, one of my fellow therapy cats received this sad diagnosis. Let me tell you briefly about her.
Like just about every other therapy cat I know of, Basil is a very special and personable cat. She a positively magical touch with those who need healing energy. When she and her human therapy partner lived in Portland, OR, she often worked at OHSU Doernbecher Children’s Hospital. And she is one of just about 35 nationally accredited Animal-Assisted Crisis Response Teams utilizing a cat. Crisis Response animals help victims and first responders during events as big as natural disasters (earthquakes, fires, floods), or as intimate as domestic violence. It’s one of the most important things you can be called on to do.
Unfortunately, Basil was recently diagnosed with an inoperable feline injection site sarcoma, and it has already metastasized to her lungs. Her human is scrambling to come up with the funds for her radiation and chemotherapy — the only things that will keep her comfortable for the time she has left. Currently, she is unemployed. She lost her job a few months ago, and with her age and management positions she should be doing, it has been hard finding work in her field. If you’d like to help Basil, her GoFundMe is here, and you can follow her Facebook page for more ways to help.
But what about FISS and your cat? Here is what you need to know.
What exactly is feline injection site sarcoma?
FISS is a very aggressive sarcoma (cancer) which attacks starting in areas where a cat has received injections. It is usually discovered as a lump near the site, and can develop any time from two months to ten years after a cat has received a vaccine or other injection. Other ways a cat can develop FISS is through injectable steroids, antibiotics, microchips and suture material. But vaccines are most common and well known.
Because the tumor is aggressive, removal (if that is even possible) has to be equally aggressive. It may involve amputation of a limb, or a large area around the mass. And even so, the cancer may have already traveled to other parts of the cat’s body, where it continues its deadly work.
And while the risk of a cat developing FISS increases with more vaccinations, it can happen after just one. So no cat receiving an injection is completely safe.
What is the life expectancy of a cat with FISS?
This varies on how far the sarcoma has spread, and how aggressive the treatment is. With aggressive surgery and treatment afterwards, life expectancy can be a year to year and a half. Longer is even possible if it looks like the cancer and its margins were removed completely. But it’s a hard cancer to catch in time and treat, and often cells have already invaded other parts of the cat’s body. It’s very rare for a cat to be cured from FISS.
What you can do to lessen your cat’s chances of developing feline injection site sarcoma
- Minimize injection exposure. Keep in mind that FISS is actually pretty rare, and vaccinating your cat is important. If your cat goes outside or interacts with other cats, they really need FeLV and rabies vaccines. And keep in mind that if your cat bites someone and they are not up to date on their rabies vaccine, they would have to be quarantined for 10 days. It’s better to be on the safe side. That said, you probably don’t need to vaccinate yearly. I opt for three year vaccines. Fewer vaccines over the years means fewer potential exposures to FISS. In addition, senior cats and cats with some medical conditions might forego vaccinations. Discuss vaccination schedules and protocols with your vet.
- Make sure your vet follows guidelines to inject different vaccines in different limbs, and preferably in the distal, or lower part of their limbs. While this doesn’t prevent FISS, it does improve the chances of removing all of the cancer through amputation.
- Examine your cat’s body regularly for any changes. If your cat is not initially comfortable with having their body felt and examined, acclimate them to it slowly, and with rewards, if you can. It is so important to be able to regularly examine your cat not just for lumps around or near injection sites, but also their mouths, paws, eyes, and behinds. The quicker you can find any irregularities, the faster you can get your cat treatment, and the better the outcome.
- Get pet insurance. FISS is just one of many illnesses your cat can develop that are very expensive to treat. Over the course of a cat’s lifetime, they are likely to have something happen that will result in big vet bills. So be prepared.
What if my cat gets feline injection site sarcoma?
You become their advocate, same as if you developed cancer yourself, or a close family member did. You discuss all the details with the veterinarian and oncologist, ask a lot of questions, discuss options, and learn everything you can. You take into account your cat’s personality and their ability to tolerate the recommended treatment. Your cat needs you more than ever, so you are with them every step of the way.
FISS is one of many truly awful medical issues that can happen to cats. I hope you and your cat never have to deal with it.
Have you ever known someone with a cat that had FISS? If you have, please discuss it in the comments.