Description

Squamous cell carcinoma (SCC) is a form of malignant cancer

that arises from cells in the outer layer of the skin and gums. An

oral SCC is diagnosed when this cancer is found in the mouth.

Oral SCC is the most common form of oral cancer in cats and is

a very serious disease. Early, aggressive treatment is necessary to

provide the best chance for good control of clinical signs and good

quality of life.

Causes

No direct cause of oral SCC has been identified in cats. Exposure

to cigarette smoke, canned fish, and flea collars are suspected to

increase the risk of oral SCC in cats, but none of these is a proven

cause. Exposure to sunlight, particularly in cats that lack protective

pigment in white skin or pink areas on the gums and lips, increases

the risk of development of oral SCC in these light-colored tissues.

Although the ears are more commonly affected by exposure to

sunlight, lesions that arise on the lips can extend into the mouth.

Chronic inflammation from periodontal disease and eosinophilic

ulcers may contribute in some cases.

Clinical Signs

Oral SCCs are aggressive, rapidly growing lesions that tend to

form ulcers. The most common clinical signs are bleeding from the

mouth, drooling, apparent pain when chewing or swallowing, and

loss of appetite. The cancer is usually easy to see when it develops

on the gum line or adjacent to the teeth. In some cats, SCC affects

the tongue or the deeper tissues in the back of the mouth. In these

cases, deep sedation or general anesthesia may be needed to allow

adequate examination of the whole mouth.

Diagnostic Tests

It is very important to distinguish oral SCC from other, similar

looking lesions in the mouth, such as severe inflammation and

other forms of cancer that have different treatments and outcomes.

Depending on the location and size of the lesion in the mouth,

your veterinarian may recommend fine-needle aspiration (extracting

cells with a needle), impression smears, or surface scrapings

to obtain cells for examination under the microscope (cytology)

or removal of a portion of the mass (biopsy) for histopathology.

These tumors can invade deeper tissues and can be aggressive, so

surgery to obtain a biopsy specimen must be carefully planned to

avoid problems that might complicate future surgical treatment.

Laboratory tests, x-rays of the chest, and an abdominal ultrasound

are often recommended to search for spread (metastasis)

of the tumor. The process of assessing the amount of cancerous

tissue present in the body is called staging the cancer . In some

cases, x-ray studies, computed tomography (CT scan), or magnetic

resonance imaging (MRI) of the jaw is done to establish the

extent of tumor growth within the mouth. Your veterinarian may

recommend referral to a veterinary oncologist (cancer specialist)

for staging and treatment planning.

Treatment Options

Treatment options for oral SCC in cats are limited. The best option

for prolonging a good quality life is well-planned, aggressive surgery

to remove the cancer. Surgery may require removal of teeth,

a portion of the jaw (mandibulectomy), or a section of cheek

bone (maxillectomy). Because radical surgery is often needed,

your cat may be referred to a veterinary surgery specialist for the

procedure.

Removal of just the mass itself may have little effect on

survival time, because these cancers recur very rapidly if any

cells are left behind. Following surgery, local radiation therapy,

chemotherapy, or other treatments may be recommended.

In some cats, palliative therapy (treatment aimed at keeping the

cat comfortable) may be tried, with medications for pain and

insertion of a feeding tube.

Follow-up Care

The schedule for follow-up visits varies depending on the treatment

method used. Following oral surgery, soft foods are fed until

healing of the site is complete. A feeding tube may also be inserted

in to the stomach, to allow the mouth time to heal. Antibiotics may

be given for any secondary infections, and an Elizabethan collar

may be applied to prevent self-trauma. Laboratory tests and chest

x-rays may be repeated periodically to monitor for spread of the

disease (metastasis) and for side effects from chemotherapy.

Prognosis

Oral SCC is an aggressive disease that severely impacts the cat’s

health and quality of life. Very few cats survive longer than 1 year

after diagnosis, regardless of the treatment they receive. Cats that

receive no therapy usually die or are euthanized within 6 weeks of

the diagnosis.