Mouth Cancer in Cats

Mouth Cancer in Cats

If your normally vibrant, healthy cat suddenly or gradually refuses to eat their food, the cause for that is most often dental disease; however, sometimes the cause may be a growth of a cancerous tumor in the mouth. According to Cornell University College of Veterinary Medicine,  mouth cancer in cats is the fourth most common type of feline cancer, and is not only painful, but can be fatal if left untreated. [1]

This article is intended to give you the information you need to know about the types of cat mouth cancer, what symptoms to look out for, the available treatment options, the prognosis, and how to reduce your cat’s likelihood of developing mouth cancer.

Types of Cat Mouth Cancer

Squamous Cell Carcinoma (SCC) is the most common type of cat mouth cancer, accounting for 70-80% of all oral tumors in cats. SCC manifests as a tumor that develops in the mouth, usually in the tissues surrounding a tooth, on the roof of the mouth, or on the underside of the tongue. SCC can also manifest in tonsils and salivary glands as well.

Fibrosarcoma is another type of mouth cancer in cats that causes destruction of normal mouth tissues and can sometimes invade bone and muscle. Fibrosarcoma usually does not create tumors, and it is less common than squamous cell carcinoma.

Other cat mouth cancer types include melanoma, lymphoma, and osteosarcoma that spreads from other parts of the body, but these types of oral cancer are much less common in cats.

Signs of Mouth Cancer in Cats

While you or your veterinarian may actually see a tumor in a cat’s mouth, oftentimes the signs are more subtle and may mimic the signs of dental disease or gum disease. Sometimes there will be no signs at all. Additional signs of feline mouth cancer can include:

  • Unexplained loss of an apparently healthy tooth (most common with SCC)
  • Bleeding from the mouth, or bloody saliva
  • Reduced appetite
  • Chewing on only one side, dropping food when eating
  • Refusing to eat kibble, will only eat soft food
  • Weight loss
  • Bad breath
  • Drooling
  • Head shy
  • Facial swelling
  • Difficulty swallowing

If you notice any of these signs, make an appointment with your veterinarian right away. If your cat does have mouth cancer, treatment is more successful and the prognosis is often better when the condition is caught early.

Causes of Cat Mouth Cancer

The cause of most oral cancers in cats is still undetermined, though SCC may have a viral component. Mouth cancer in cats is also believed by the scientific community (though not confirmed) to be a result of exposure to: 

  • Environmental carcinogens (like secondhand cigarette smoke or other tobacco products)
  • Consumption of canned foods containing tuna
  • Chemicals in flea collars [2]

Studies showed that cats that wore flea collars had five times the risk of developing mouth cancer. In addition, any chronic inflammation or irritation in the mouth, including inflammation associated with periodontal disease, increases the risk of the development of oral tumors.

Diagnosing Oral Cancer in Cats

Diagnosis of cancer of the mouth in cats starts with a full physical examination by a veterinarian. To get an accurate diagnosis, your veterinarian will likely need to sedate your cat for a complete oral examination and radiographs (X-rays) of the mouth. They will also recommend bloodwork to assess the overall health of your cat and rule out other medical conditions. In some cases, they may recommend an MRI or CT scan, and in most cases, they will either submit a portion of any suspicious lesions or remove the tumor or for biopsy to determine the type.

Treating Cat Mouth Cancer

Treatment of mouth cancer in cats depends on the type of tumor, but it typically involves surgery and radiation. Sometimes chemotherapy and molecularly targeted therapies are utilized. In addition, cats with mouth cancer are also treated for pain and may need nutritional therapy, such as a feeding tube, to support them through their recovery.

Cost to Treat Cat Mouth Cancer

The cost to treat mouth cancer in cats typically ranges from $1,000-$7,000, depending on the tumor type, location, and degree of malignancy. 

Treatment expenses include:

  • Cost of diagnosis
  • Cost of surgery
  • Costs of radiation and chemotherapy (if indicated)
  • Follow-up costs

Prognosis for Cats With Mouth Cancer

A cat’s prognosis depends on tumor type, location, and if the cancer has spread to other parts of the body. Benign tumors are typically successfully treated with surgical removal and sometimes radiation, and in general, have a good prognosis. Malignant tumors are treated surgically with varying levels of success, depending on the type of tumor, where it is located, and if it has spread to other parts of the body. 

Unfortunately, by the time SCC is usually diagnosed, the tumors are too large and the cancer has often spread to the local lymph nodes. In these circumstances, prognosis is poor, and only palliative treatment is available.

How to Prevent Mouth Cancer in Cats

While there is no fool-proof way to protect your cat from mouth cancer, there are proactive steps you can take to lower your cat’s risk, such as:

  • Reduce or eliminate your cat’s exposure to second-hand tobacco smoke.
  • Talk to your veterinarian about flea collars.
  • Talk to your veterinarian about the type of food you feed your cat, and avoid feeding tuna. (The EPA recommends no more than 1.5 ounces [45 grams] of canned tuna per week for adult cats.)
  • Brush your cat’s teeth regularly, pay attention to their oral hygiene, and routinely examine your cat’s face (and inside of their mouth if they will let you) for anything suspicious.
  • If your cat has dental disease, have it treated by a veterinarian.
  • Have your cat’s mouth examined yearly by a veterinarian. (If your cat has a history of dental disease and is older than 7, schedule twice yearly oral examinations with your veterinarian.)
  • Remember that cat mouth cancer carries a better prognosis if caught early. If you notice any of the signs listed in this article, talk to your veterinarian right away.


  1. “Oral Cavity Tumors.” Cornell Feline Health Center. Retreived from[…]/health-information/feline-health-topics/oral-cavity-tumors 
  2. “A Review of Feline Oral Squamous Cell Carcinoma” (2016, October) Today’s Veterinary Practice. Retrieved from

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