[Written by a Veterinarian] What is Feline Squamous Cell Carcinoma? Symptoms, Causes, Treatments, and Daily Care

　"There's a lump in my cat's mouth," "I found a lump on its nose or ear"—one of the diseases that could be considered in such cases is Feline Squamous Cell Carcinoma (SCC). This type of cancer often occurs in the oral cavity or skin and progresses rapidly, making early detection extremely important. In this article, a veterinarian will provide an easy-to-understand explanation of thesymptoms, causes, treatments, and daily care.

What is Feline Squamous Cell Carcinoma?

Characteristics of Squamous Cell Carcinoma (Malignant Tumor of the Skin and Mucous Membranes)

Squamous cells are cells that form the skin and mucous membranes. Squamous cell carcinoma is a malignant tumor derived from these squamous cells. It is a common tumor in cats, especially often occurring in the mouth, and is said to account for 70-80% of oral tumors in cats. Squamous cell carcinoma is characterized by its local invasiveness, meaning that tumor cells easily spread to surrounding tissues, but it is less likely to metastasize to distant sites.

Commonly Affected Areas (Oral Cavity, Nose, Ears, Skin)

Squamous cell carcinoma can occur in various places such as the skin, ears, nose, claws, and oral cavity. Those that develop in the mouth or jaw tend to grow large, leading to difficulties such as inability to eat.

Common in Older Cats, but Can Occur in Younger Cats Too

The average age at which squamous cell carcinoma develops is said to be 14 years old, and it occurs more frequently in older cats. However, it can also occur in younger cats, so being young does not guarantee safety.

Symptoms of Feline Squamous Cell Carcinoma

Lumps, Ulcers, and Bleeding in the Mouth

In the early stages of squamous cell carcinoma in the oral cavity, lesions that are indistinguishable from gingivitis or stomatitis, such as redness in the mouth, may appear. As the tumor grows, ulcers may form, and the cat may experience pain when eating. If the tumor grows further, it will occupy the oral cavity, causing the tongue or drool to constantly hang out, and the cat may be unable to close its mouth. As the ulcers worsen, bad breath will become severe.

Increased Bad Breath and Drooling

As squamous cell carcinoma spreads, the tumor grows larger and ulcers form. If the ulcers become secondarily infected with bacteria, pus will be discharged, leading to turbid drool with a foul odor. The bad breath will also be quite strong.

Lumps and Sores on the Nose or Skin

When squamous cell carcinoma develops on the nose or jaw, the tumor forms in the bone, appearing as a lump. As the tumor grows, it can cause fractures or deform the shape of the face.

Squamous cell carcinoma on the skin often occurs on the ears, nose, or claws, where the skin suddenly turns red and becomes inflamed. Scabs may also form, which can be mistaken for dermatitis, but the characteristic of squamous cell carcinoma is its progressive spread.

Progression Leads to Loss of Appetite and Weight Loss

Squamous cell carcinoma progresses rapidly, and those that develop in the mouth or jaw tend to grow larger. As it progresses, the cat may have difficulty chewing or swallowing, leading to a decreased appetite and weight loss. Due to severe pain, chewing may also become difficult.

Causes and Risk Factors

UV Radiation Exposure

While many causes of feline squamous cell carcinoma are still unknown, UV radiation is thought to be a contributing factor. The occurrence in white-coated cats and in areas with thin pigmentation suggests that UV radiation may be a cause.

Environmental Risk Factors

Although the precise cause of squamous cell carcinoma is still unknown, reports suggest that tobacco smoke and flea collars may be risk factors.

Treatment and Prognosis

Surgical Removal

If there is no metastasis, complete surgical resection is the first choice. However, if it develops in the jaw, it may be necessary to remove the jaw, and in some cases, the tongue as well. In such cases, the cat will not be able to eat on its own, so an esophageal tube or gastrostomy tube will be placed, and food will be administered through it. Since the shape of the face will change significantly, some owners may find it difficult to accept.

Surgical removal of jaw and oral squamous cell carcinoma is also performed as palliative care, aiming for pain relief and improvement of quality of life, in addition to treatment.

Radiation Therapy and Chemotherapy

If there is metastasis or if the tumor cannot be completely removed surgically, radiation therapy or chemotherapy is performed. Neither of these can achieve a complete cure; their purpose is to suppress tumor growth and alleviate pain.

Prognosis Differences Based on Stage of Progression

Feline squamous cell carcinoma progresses rapidly and, while distant metastasis is uncommon, it is a highly locally invasive tumor that spreads to nearby tissues.The prognosis without treatment is approximately 2 months. If completely removed by surgery, survival for over a year can be expected. In cases of palliative care, some reports indicate that the average survival period does not significantly differ from that without treatment.

Daily Care and What Owners Can Do

Regular Checks

In the early stages of squamous cell carcinoma in the oral cavity, it may be indistinguishable from gingivitis or stomatitis. Therefore, regularly check your cat's mouth and observe it closely for any abnormalities. If it's difficult to check at home, have it checked at a veterinary clinic.

If a cat develops squamous cell carcinoma, the prognosis can be poor even with treatment due to its rapid progression. Recurrence is also possible, so it's necessary to have your cat checked at the veterinary clinic every few weeks for recurrence and to ensure there's no metastasis to nearby lymph nodes. However, abnormalities can appear sooner, so try to check daily at home.

Adjusting Diet Content

In cases of oral squamous cell carcinoma, eating often causes pain, making it difficult for the cat to consume food. It may be beneficial to offer soft foods or soups that require less chewing.

If tube feeding becomes necessary, the diet must be changed to prevent the tube from clogging. Liquid diets are suitable for tube feeding. Tube feeding cannot be done quickly, so approach it with ample time and patience.

Key Points for Daily Care

Squamous cell carcinoma requires post-operative care. For example, if the jaw has been removed, not only is tube feeding necessary, but care for drooling is also required as saliva will constantly drip.

The area where the tube is inserted is secured with sutures, so check daily for any loosening of the sutures, whether the sutures have come off, if the tube is dislodged, or any abnormalities in the skin around the tube. Disinfection may also be necessary. When feeding through the tube, ensure that the tube is properly inserted into the stomach or esophagus before administering food. After feeding, flush the tube with water to prevent clogging.

Cats that have had their jaws removed will drool constantly, and the skin exposed to saliva can develop dermatitis. To prevent this, use a bib or gently wipe the area clean.

Summary | Facing Feline Squamous Cell Carcinoma

Squamous cell carcinoma progresses rapidly, and in its early stages, it is often difficult to distinguish from other diseases. Chronic dermatitis, gingivitis, or stomatitis should raise suspicion of squamous cell carcinoma. Do not wait; consult a veterinarian. Squamous cell carcinoma in the mouth and jaw, in particular, is common and tends to grow large. Symptoms include foul-smelling breath, drooling, and loss of appetite. If such symptoms are observed, seek veterinary attention immediately.

Unfortunately, squamous cell carcinoma is a fast-progressing tumor with a high recurrence rate. Various types of care may be necessary. Continue to show love until the very end and support your cat so it can live the best possible life for as long as possible.