The cancer cats get in their mouths

I really couldn’t come up with a catchy title. It’s a sucky disease. Cancer sucks. So the title sucks. It’s a theme.

But let’s talk about Squamous Cell Carcinoma. It’s a type of cancer that can occur in a variety of places. Humans get it on their skin (reason to wear your sunblock!!). Dogs and cats can get this kind of cancer on their skin as well, but it is not very common, because they have fur for sunblock! Because the skin version is related to UV exposure (like our version) it tends to affect more light colored animals, and in areas with thin fur, like the nose, tips of ears, etc.

We’re talking about a different version of Squamous Cell Carcinoma. A much deadlier, suckier one.

This is the most common oral tumor of cats. If you find a cat with a mass growing anywhere in the mouth (lips, gums, palate, etc) we assume it is a squamous cell carcinoma until proven otherwise. If we wanted to 100% confirm it was this cancer, a biopsy of the growth under general anesthesia is the best way. Some vets will try to cut back the tumor (debulking) while they are at it, but this does not really improve the prognosis. This cancer does not tend to metastasize, or spread throughout the body, which is a good thing. So why do we hate it so much?

The tumor grows in the mouth and can invade the bones of the skull. We use the term “locally invasive” to indicate it does not spread throughout the body, but really can get out of hand in the area it is in. We hate this disease because it makes us euthanize a cat who is otherwise healthy. From the neck down, the cat is healthy and normal! But this awful tumor invades the mouth, preventing the cat from eating. We obviously don’t want the cat to starve to death, so humane euthanasia is eventually chosen as opposed to starvation.

cat tumor

In some lucky cats, the tumor grows on the bottom jaw, which we can surgically remove (yes, cats can live with a partial bottom jaw!). This is often best performed by a specialist, as it is a very involved procedure. When the tumor invades the upper jaw (the maxilla) that connects to the face, it can even effect the eye! Obviously, we can’t surgically remove half your cat’s face. I have had some owners pursue radiation therapy for these cats. Unfortunately, the eye is usually in the field of radiation, and may suffer because of it. But some of these tumors do shrink a little.

What about a feeding tube? If the whole cat is healthy, and it just can’t eat, can’t we do it for them? I have had a couple clients who could not let the cat go, and we did a feeding tube. It does not help significantly improve the quality of life of these cats. The tumor continues to grow, eating away at the skull. We have teeth falling out because the bone that holds them in is so abnormal. We have a cat drooling blood all the time, and they are generally very uncomfortable.

The most common symptom we see with oral squamous cell carcinoma is the breath. I often joke I can diagnose this disease simply by walking in the room. It is a smell like no other – a smell of rotting, decaying tissue. Sometimes the swelling in the face is apparent from across the room, while other times we have to open the mouth to look.

This disease sneaks up on people…how often do YOU look in your cat’s mouth? And if you are not keeping up on your cats dental care, you may just think it’s a bad tooth you’re smelling. Bloody drool is another common symptom, but again, people often blame dental disease (which the cat very well may have as well!).

So if you notice your cat’s breath smelling extra bad, get him to the vet! If caught early, and if they happen to grow in the right place, some of these tumors may be resectable. Otherwise, knowing what you are dealing with lets you focus on making your cats remaining weeks/months as good as possible.

Posted in Dental health, Feline specific.


  1. Thank you for writing this. I had to put my 16 year old cat down today, because of this very thing. I took her to the vet last week, as she started drooling and we all thought it was a tooth issue. (The vet didn’t check under her tongue.) I felt a lump the same day as her vet visit, but we all decided to look at it, once she was sedated. However we couldn’t do that yet, because she was diagnosed with a heart murmur and needed to check that out first. *she was also diagnosed with hyperthyroidisim this past week, after blood tests, but it was in the very early stages.

    I woke up this morning to her bleeding profusely from her mouth and it took two vet visits today to diagnose her. We didn’t need to wait for a biopsy – the lump I found under her chin – was actually a tumor that had grown from under her tongue and was about the size of a grape and hard.

    We made the decision to let her go today, rather than prolonging suffering on her part. There wasn’t any way to stop the bleeding and it was just going to keep growing.

    I couldn’t let her die in more pain – so I did what was easier for her. And reading this makes it a little easier to deal with the emptiness and pain I feel in my heart. She was everything to me and I hope I proved that, for ensuring she didn’t suffer and she left this world happy and in my arms.

    • Michelle, I just read you note. My cat was 14 and I had to let her go this past Monday. About 5 weeks ago we discovered a large sore under her tongue. We tried antibiotics in case it was just a canker sore. Within 2 weeks it had tripled in size so we did the biopsy. It was Squamous Cell Carcinoma. For a couple of weeks I thought she would get better then her mouth started bleeding and we found another tumor. It broke my heart to let her go but I could not watch her suffer. I’m sorry for your loss.

  2. This article has given some clarity for a very difficult situation. My Persian developed a lump that bled in August. After treating with a topical cream and antibiotics it has progressed. He also had a grade four heart murmur so I decided not to have him under go the biopsy. The specialist did feel it was cancer in his chin. It’s been five months now with daily pain medication. He is drooling blood; struggling to eat and does not clean himself anymore. My vet has performed progress visits and feels he if continues to eat there is quality of life.

    I have felt at a crossroads to prolong his life or make the decision to end it humanely before it progresses more. We have another vet visit this week; I hope the vet will help me make the ethical decision but I fear it will be more advice to continue to feed him at any cost.

    He isn’t the same cat and it breaks my heart to see him succumb to this disease.

  3. I found some comfort reading this article. It was very informative and helped me understand things more clearly. We just put down our 10/11 year old cat – Not sure of his exact age since we adopted him…His symptoms started with drooling & for a week we thought he had some sort of virus. He was eating & seemed his usual self so we did not go to the vet right away.
    At the first vet visit blood work was all normal. It was not until the second vet visit that the growth was discovered. An antibiotic shot & pain medication was given. We were hoping it maybe was a clogged saliva gland. By the third vet visit we were told the bad news.
    Our poor guy was trying to groom himself but he still looked a mess. Our vet said only the tip of his tongue was working & the rest of his tongue was hard like a rock. We never noticed any bad breath but the drool sometimes appreared pink on his bedding.
    About two weeks from the start of his symptoms he stopped eating. We could tell he wanted to eat but he could not. Really heartbreaking. That is when we knew he had to be put him down ASAP to end his suffering. We will miss the presence of the big guy very much.
    Looking back I do recall him sometimes looking like he was having a “difficult” /messy time chewing his hard foods compared to our two much younger cats. He was on the heavier side & was nourished so I just attributed it to him getting older perhaps aging teeth.

  4. Hi thank you to all who have posted, it gives me a small amount of comfort that I am doing the right thing for our big boy by making arrangements today to have our Teddy put to sleep, he has been drooling but still eating and appears otherwise normal, however vet has found a large mass on bottom jaw hence drooling constant and suggested we put him to sleep to save him any pain going forward.Vet was very adamant this is the only option.
    Hardest decision as he appears normal otherwise,

  5. So can my cat still eat with the surgery of getting the tumor removed? And can I give my cat medical marijuana to open and kill the tumor ?

  6. Kile, my cat had it. We removed it once but it came back with a vengeance. I had to let her go. The vet said we would have to remove most of her tongue and jaw and I would not do that to her. That is cruel. We have to know when to say good bye and let them have some dignity in death. It was he hardest thing I’ve ever done but I could not allow her to be cut up and live on pain meds. I’m sorry for your cat.

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