Oral Cancer in Cats-Causes, Symptoms & Treatment


What is oral cancer?   Causes   Symptoms   Diagnosis   Treatment

Oral cancer in cats

At a glance:

  • About: Oral cancer is any cancer in the oral cavity, the most common type is squamous cell carcinoma.
  • Causes: Flea collars, second-hand cigarette smoke, and diet.
  • Symptoms: Lump in the mouth, reluctance to eat, pain, drooling, bad breath
  • Diagnosis: Blood tests, imaging, and biopsy.
  • Treatment: Surgery, radiation or chemotherapy, and supportive care.

What is oral cancer?

Also referred to as malignant neoplasms or malignant tumours, cancer is the uncontrolled division of cells that normally should be restricted in their growth. Tumours can be malignant (cancerous) or benign. Benign tumours grow slowly, are surrounded by a capsule and do not invade neighbouring tissue or spread to other areas.

Ten percent of all cancers in cats are oral cancer and squamous cell carcinomas (SCC) are the most frequent type. This cancer accounts for 60-70% of all oral cancers in cats. The next most frequent are fibrosarcomas, other cancers include lymphoma and malignant melanoma.

This article will refer to SCC as it is the most common type of oral cancer in cats.

SCC is a particularly aggressive cancer, rapidly growing and invading nearby tissues and bone. It is rare for SCC to metastasize to other areas of the body. The average onset of the disease is 12 years.


Oral cancer in cat

The exact cause(s) of squamous cell carcinoma are still not completely known, but contributing factors include:

Flea collars

One study found that cats who wear flea collars are five times more likely to develop SCC, due to the proximity of the collar to the oral cavity.

Passive smoking

Exposure to cigarette smoke inside the home puts cats at risk. Not only do they inhale the smoke, but they also ingest it when they groom.


Canned cat food, especially tuna flavour showed a threefold increase in the risk of developing SCC.


Symptoms of oral cancer in cats

Unfortunately, cats are extremely good at hiding signs of pain and the oral cavity isn’t out there in the open so to speak, so pet owners may not become aware until the disease is advanced. Early detection offers a better prognosis.

  • Ulcerated, red lesion on the gums, tongue or underneath the tongue
  • Difficulty eating and/or a loss of appetite
  • Painful mouth and/or face
  • Bleeding in the mouth
  • Bad breath
  • Swollen face
  • Loose teeth
  • Enlarged lymph nodes under the jaw
  • Drooling
  • Grooming less
  • Weight loss due to loss of appetite


Your veterinarian will perform a complete physical examination of your cat, carefully checking the oral cavity for lumps and loose teeth (which can be indicative of bone loss) as well as checking local lymph nodes for signs of enlargement. He will obtain a medical history from you, including how long you have noticed the growth and other symptoms.

Diagnostic workup

Baseline tests:

Biochemical profile, complete blood count, and urinalysis to evaluate the overall health of your cat. The biochemical profile may reveal high blood calcium due to bone disintegration (lysis).


X-rays will also be taken while the cat is under anesthesia to determine the extent of bone involvement.

Chest x-rays to look for signs of metastasis in the lungs.


Biopsy of the growth which will be sent to a laboratory for evaluation.

Once a diagnosis has been made, your veterinarian will stage the tumour which will include the size of the tumour, bone invasion and regional lymph nodes.


The outcome for cats with oral cancer is poor, with only 10% surviving the one year mark. In many cases, surgery is not practical, even when surgical removal occurs, the recurrence rate is very high, in which case, palliative care is recommended.

Treatment can be difficult due to cancer quickly invading surrounding tissues.

  • If the tumour is found early enough and is in the front portion of the mandible (lower jaw) surgery (mandibulectomy) may be performed.
  • Cryosurgery (freezing) on small tumours.
  • Radiation therapy may be recommended before surgery to shrink the cancer or after surgery to kill off any remaining cells.
  • Radiotherapy or chemotherapy for tumours that are too large, or in a part of the mouth which makes it impossible to surgically remove.

Palliative care

For tumours too advanced to treat, the following treatment options can improve your cat’s quality of life.

  • Non-steroidal anti-inflammatory drugs (NSAIDS) such as piroxicam can slow down tumour growth.
  • Antibiotics will be prescribed to treat bacterial infections which may occur, these are common in cats with oral cancer.
  • Analgesics to relieve pain.
  • Nutritional support is important as it is common for cats to be reluctant to eat due to pain, this may involve the placement of a feeding tube so that adequate nutrition is maintained.

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