Cat Mouth Cancer: Types, Symptoms, Treatment & More

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When cats suddenly or gradually refuse to eat their food, its possible that dental disease could be the reason, with mouth cancer being one of the more serious dental problems. According to Cornell Feline Health Center, oral cavity cancer is the fourth most commonly diagnosed cancer in cats. There are many different types of mouth cancer in cats, and some are more common than others.

An important part of pet parenthood is understanding how to support your furry friend's health. Read on to learn the signs of cat mouth cancer, the available treatment options and how to reduce your cat's risk of developing it.

What Causes Mouth Cancer in Cats?

The cause of mouth cancer in cats is still largely unknown. Oral squamous cell carcinoma (SCC), the most common mouth cancer found in cats, may have a viral cause. The scientific community at Today's Veterinary Practice also largely believes SCC can be caused by exposure to environmental carcinogens, such as chemicals in flea collars, consumption of canned tuna and secondhand smoke from cigarettes. A study in the Journal of Veterinary Dentistry showed that cats who wore flea collars had an increased risk of developing mouth cancer.

In addition, any chronic inflammation or irritation in the mouth, such as inflammation associated with dental disease, increases the risk of mouth cancer.

Persian cat with veterinarian doctor at vet clinic

What Are the Types of Mouth Cancer in Cats?

The most common mouth cancer in cats is SCC, accounting for 70% to 80% of all cat mouth cancer. SCC creates a tumor in the mouth either in the tissues surrounding a tooth, on the underside of the tongue, on the roof of the mouth, on the tonsils or on the salivary glands.

The second most common type of oral cancer in cats, fibrosarcoma, destroys gums, bones and muscles in the mouth. Other types of feline mouth cancer include lymphoma, melanoma and osteosarcoma. These types of cancer spread from other parts of the body and are much less common than SCC or fibrosarcoma.

What Are the Signs of Cat Mouth Cancer?

In some cases, you or your veterinarian may be able to see a tumor in your cat's mouth. Other times, the signs are more subtle, and sometimes there are no signs at all. Mouth cancer can also mimic the signs of dental disease.

Some of the signs associated with feline mouth cancer include:

  • Sudden loss of an apparently healthy tooth (seen in SCC)
  • Bloody saliva that's red or pink-tinged
  • Unexplained drooling
  • Picky or decreased appetite, leaving food in the bowl or only eating soft food
  • Dropping food when eating
  • Plaque and tartar buildup on only one side of the mouth
  • Weight loss
  • Halitosis (bad breath)
  • Pulling away or not allowing their head to be touched
  • Swelling on one side of the face

How Is Cat Mouth Cancer Diagnosed?

If you suspect mouth cancer or any oral disease in your cat, schedule an appointment with your vet as soon as possible. They'll conduct a full physical examination and may need to sedate your cat to examine their mouth and take X-rays. Your vet may also order other tests, including bloodwork and a biopsy of any masses within the mouth to determine if it is cancer. More rarely, they may recommend an MRI or CT scan.

How Is Cat Mouth Cancer Treated?

Following a diagnosis, your vet will develop a treatment plan that will depend on the type of tumor, how far it's spread and its location in your cat's mouth. Treatment options can include surgery, radiation and chemotherapy. Cats with mouth cancer are also treated for discomfort, and if they aren't eating, they may have a temporary feeding tube placed to support them through recovery. Treatment costs can range widely depending on what therapies they undergo.


Benign oral tumors (ones that do not spread throughout the body) are usually successfully treated with surgery, and the prognosis is good. Malignant mouth cancer is also treated surgically, but the success of treatment varies. Unfortunately, the prognosis for cats with malignant mouth cancer is often poor because the disease typically isn't caught until the later stages, at which point it may have spread to the lymph nodes or other parts of the body.

In these circumstances, your vet or veterinary oncologist will focus on palliative care, which aims to keep your cat as comfortable and pain-free as possible.

How Can You Prevent Mouth Cancer in Cats?

While you can't protect your cat against mouth cancer entirely, you can take steps to lower the likelihood that they'll develop it. Here are some of the ways you can reduce the risk of oral cancer in your feline friend:

  • Eliminate exposure to secondhand smoke.
  • Ask your vet about the best flea control method for your cat.
  • Get your vet's recommendation on how often to feed your cat tuna, or simply avoid sharing canned tuna with your cat.
  • Brush your cat's teeth daily and, when you do, examine their face and mouth for anything suspicious.
  • Seek treatment for any type of dental disease as soon as possible.
  • Have your vet examine your cat's mouth yearly. If your cat has a history of dental disease and is older than 7, bump it up to twice a year.

Cat mouth cancer is easier to treat if it's caught early. If you notice any of the signs associated with feline oral cancer, schedule an appointment with your vet right away. Understanding what to look out for when it comes to your cat's health helps you be the best pet parent you can be, and it helps your cat get the care they deserve.

Contributor Bio

Dr. Sarah Wooten

Dr. Sarah Wooten

A 2002 graduate of UC Davis School of Veterinary Medicine and certified veterinary journalist, Dr. Sarah Wooten has 16 years experience in small animal veterinary practice, is a well known international speaker and writer in the veterinary and animal health care spaces, and is passionate about helping pet parents learn how to care better for their fur friends.