Feline oral squamous cell carcinoma

Oral squamous cell carcinoma is a nasty disease in cats. Frequently, these cancers are not identified until the lesion has progressed significantly with associated oral pain and halitosis due to bacterial infection.

Oral squamous cell carcinoma is a cancer that arises from the cells lining the mouth and throat including the gums, tongue, cheeks and tonsils. This cancer has an ability to grow invasively into the surrounding tissues and the visible part of the tumour is all too often just the proverbial tip of the iceberg.

Most cats with this disease are middle-aged (average 11-12 years), although it has been described in cats from 2-18 years old.

Presenting complaints commonly include deformity of the face, loose teeth (which may result in difficulty eating), weight loss and halitosis. Other, more subtle signs include mouth pain and dribbling.

You should be aware that it is important to get all mouth problems checked out as there are many other conditions that can affect the oral cavity and resemble squamous cell carcinoma, such as eosinophilic granuloma complex, and mouth ulcers.

When examining your cat your vet may see a mass or a sore in your cat’s mouth or throat. Biopsy provides the best means of diagnosis of oral cancers. In older cats with dribbling or other evidence of mouth pain, your vet should always consider the possibility of oral squamous cell carcinoma as a cause. Sometimes oral squamous cell carcinoma is misdiagnosed as a dental complaint.

Early diagnosis is the cornerstone of successful therapy. Undoubtedly, many cases are presented to their veterinary surgeon at a time when the disease has already progressed too far. Feline oral squamous cell carcinoma rarely spreads to the lymph nodes or through the blood stream. Despite this, following diagnosis or on suspicion of a diagnosis, it is important that the lymph nodes and the lungs are assessed to check that there is no evidence of cancer spread.

Sadly, at this time the prognosis for affected cats is usually poor regardless of treatment. Multiple different treatments have been explored including radical surgery, chemotherapy, radiation therapy, hyperthermia (heat treatment), cryotherapy (freezing), anti-inflammatory therapy and combinations of the above.

Consistently, studies indicate an average life expectancy of only 1 to 3 months. In some cases, the cancer arises in a site that is amenable to surgical excision; these are usually small cancers in the cheek or the mandible.

A small proportion of cases do respond well to radiotherapy with about 1 in 10 of these cases living for a year or more. Side effects from radiotherapy are few. While skin and gum irritation is described, this happens extremely infrequently using the treatment strategy that most UK oncologists favour.

Paradoxically, the greatest problems arise in the patients who demonstrate an excellent response to therapy. If a large proportion of a cancer is killed by the radiation, this can leave a hole in the mouth which may harbour infections or may allow food and water access to the nasal cavity.