Mouth Cancer in Cats

Mouth cancer is cats is commonly caused by the oral malignancy known as squamous cell carcinoma. In fact, about 80% of feline oral tumours will be SCCs, and these are what this article will focus on. 

This type of cancer invades surrounding structures of the mouth including the mandible, maxilla, dental arcade, tongue and other portions of the oral cavity.  Squamous cell carcinoma cancer is often detected too late and treatments prove ineffective. Mouth cancer also presents similar symptoms to periodontal disease, so early detection and a proper diagnosis is essential.

If your cat begins refusing food, has lost teeth and has noticeably bad breath, the possibility of mouth cancer should be considered. Mouth cancer is a very aggressive, fast-growing cancer that is not usually noticed until the disease has reached advanced stages. Mouth cancer can be a tumor located anywhere within a cat’s oral cavity including the lips, tongue, cheeks, roof of the mouth, upper or lower jaw, and back of the mouth. Mouth cancer is not connected to any breed, age or sex of cat, but experts believe second-hand smoke could contribute to its occurrence.

Mouth cancer in cats may be noted by a visible tumor or mass of the oral cavity. Unfortunately, squamous cell carcinoma tumors that grow within the tissues of the tongue, tonsils, roof, or back of the mouth often go unnoticed for a long time. Most pet owners realize their cat has developed a health problem after noticing some or all of the following symptoms:  

• Bloody nose 
• Mouth pain
• Halitosis (bad breath) 
• Weight loss
• Facial swelling
• Dropping food during a meal
• Increased salivation 
• Bleeding from the mouth
• Difficulties eating and drinking
• Loose teeth or loss of teeth

The exact cause of mouth cancer in cats remains unknown. No breed, sex or age of cat is more susceptible than another, yet most felines are considered seniors when they are diagnosed (about 10-12 years old). For many, it is likely genetic. Experts believe that mouth cancer, like many other types of cancer, can be caused by environmental factors and diet. Your cat may be at a higher risk of developing mouth cancer if he or she:

• Lives with owners who smoke 
• Consumed a large amount of canned cat food, especially those containing a high tuna content
• Uses a flea collar

Diagnosis of mouth cancer in your cat will begin with a review of your cat’s medical history and a discussion with the veterinarian. The vet may ask you what type of symptoms your cat has been displaying, when they were first noticed and for how long. Upon physical examination, your cat’s mouth will be fully examined and the tumour will be visually inspected. Blood work may be requested to assess the feline’s overall health before proceeding with a tissue biopsy. A biopsy of the mass will confirm the diagnosis. Squamous cell carcinoma cancer often invades the bony structures of the jaw, so an x-ray of the skull may be done before or after the biopsy. Mouth cancer is very aggressive and can spread to the lungs and lymph nodes, therefore, a CT scan may be requested to check for other tumor masses within the upper body.

The treatment of mouth cancer depends on the location of the squamous cell carcinoma mass and if any bone is involved. Surgically removing the tumor from the cat’s mouth is ideal, but not always possible. If the tumor is located in the front portion of the mouth, the tumor can often be removed along with a small portion of the jaw bone. However, if the tumor is in the back of the mouth, roof of the mouth or has spread to vital structures, removing the mass may not be viable. Some veterinarians treat mouth cancer in cats with a combination of radiation therapy and chemotherapy, not to treat the disease, but to improve quality of life. Therapeutic treatments can temporarily shrink the mass and allow the feline to eat or have a feeding tube placed to provide nutritional support. Treatment options for mouth cancer in cats varies from case to case, so ask your veterinarian about the best plan for your cat and his/her condition. 

The prognosis for cats diagnosed with mouth cancer is rather poor, even after treatment. The reason for this is because mouth cancer is not usually noticed until the cancer has spread and symptoms begin to make themselves present. Treatments of the disease then begin after the cancer has reached its most aggressive stage, and only cats that have undergone surgery have the longest survival rate. Pet owners who choose not to treat their cat’s mouth cancer should expect their cat to live approximately three months.