Squamous Cell Carcinoma in Cats: Why the Nose, Ears and Mouth Are at Risk
Squamous cell carcinoma, commonly referred to as SCC, is one of the most frequently encountered skin and oral cancers in cats. It is locally aggressive, tends to invade surrounding tissue, and is diagnosed most often in older cats — typically those over ten years of age. Understanding where this cancer arises and why certain areas of the body are disproportionately affected is important for early detection and timely intervention.
What Is Squamous Cell Carcinoma
SCC originates in squamous cells, the flat, scale-like cells that make up the outermost layer of skin and mucous membranes. When these cells undergo malignant transformation, they form tumours that grow and invade locally. Unlike some cancers, SCC in cats does not frequently spread to distant organs early in the disease, but its local invasiveness makes it clinically serious. Left untreated, it destroys surrounding bone, cartilage, and soft tissue.
Why Certain Sites Are Vulnerable
The nose and ear tips
The most well-established risk factor for cutaneous SCC in cats is ultraviolet light exposure, particularly in areas where skin pigmentation is low or absent. White cats, or cats with white colouring on the face and ears, have little melanin in these areas to absorb UV radiation, leaving the underlying skin unprotected. The ear tips, the nasal planum (the flat, leathery surface at the end of the nose), and the eyelids are thin-skinned areas with minimal hair coverage that receive direct, cumulative sun exposure across a cat's lifetime.
The disease often progresses through identifiable stages. Initially, owners may notice what appears to be a minor skin irritation — perhaps some redness, mild crusting, or a small sore that does not heal. These early lesions are sometimes dismissed or mistaken for cat flu, sunburn, or a minor wound. Over months, the lesion deepens, ulcerates, and the tissue begins to erode in a manner that makes the extent of the damage visually obvious.
The oral cavity
Oral SCC is a distinct form of the disease and one of the most common oral tumours in cats. It typically arises under the tongue, along the gums, or at the back of the mouth, and it does not share the same solar UV aetiology as cutaneous SCC. The precise cause of oral SCC in cats remains an area of ongoing research. Environmental tobacco smoke, flea collar use, and dietary factors have all been proposed as potential contributors, though evidence is not definitive for all of these.
What is clear is that oral SCC is highly invasive at the time of diagnosis in the vast majority of cats. It frequently involves the underlying jawbone, making surgical removal difficult and often incomplete.
Recognising the Warning Signs
Early recognition is critical and makes a material difference in treatment outcomes, particularly for cutaneous lesions. Signs to be aware of include:
- A crusty, sore, or non-healing wound on the ear tip, nose, or eyelid
- Loss of normal tissue architecture at the nasal planum — a roughened, irregular, or ulcerated surface
- Ear tips that appear thickened, scabbed, or start to curl inward
- Difficulty eating, dropping food, or chewing on one side only
- Drooling, sometimes blood-tinged
- Foul odour from the mouth
- Swelling or asymmetry of the jaw or face
- Weight loss associated with difficulty eating
Any non-healing skin lesion on a white or fair-coated cat should be assessed by a vet promptly. The temptation to wait and see is understandable, but early-stage SCC is genuinely more amenable to treatment than advanced disease.
Diagnosis
A definitive diagnosis requires tissue sampling. Fine needle aspiration can provide cytological information in some cases, but biopsy with histopathology is the gold standard and provides information about tumour margins and depth of invasion. For oral lesions, skull radiographs or advanced imaging such as CT scanning are important for assessing the extent of bone involvement before surgical planning.
Treatment Options
Surgery
For early cutaneous SCC of the ear tips, surgical removal — pinnectomy — is often curative. Cats tolerate this procedure well and the cosmetic outcome, while altered, does not significantly affect quality of life. Early nasal planum lesions may similarly be addressed with planum resection, though this requires specialist surgical experience.
Oral SCC is considerably more challenging to treat surgically because of the local invasiveness and the structures involved. Mandibulectomy or maxillectomy — removal of part of the jawbone — may be performed, but achieving clean margins is difficult, and recurrence rates are high even after aggressive surgery.
Radiotherapy
Radiation therapy is used in some centres for both cutaneous and oral SCC, either alone or following surgery. Response rates vary, and access to veterinary radiation oncology facilities is not universal. For cats where surgery would be highly morbid or where incomplete margins are anticipated, radiotherapy may offer meaningful disease control.
Photodynamic therapy
Photodynamic therapy is a treatment option used at some veterinary referral centres for superficial cutaneous SCC lesions. A photosensitising agent is applied to the tumour, which is then activated by a specific wavelength of light to destroy cancer cells locally. It is most suitable for small, early-stage lesions.
Palliative management
For cats with advanced oral SCC where curative intent is not realistic, the focus shifts to maintaining quality of life for as long as possible. Pain management is central to this approach. Non-steroidal anti-inflammatory drugs, opioids, and adjunctive pain management strategies are used alongside nutritional support, sometimes delivered via oesophagostomy tube when eating becomes too difficult or painful.
Prevention and Sun Protection
For cats at risk — particularly white cats or those with white facial markings — limiting sun exposure during peak UV hours (generally between 10am and 4pm) is the most effective preventive measure. Keeping cats indoors during these hours, providing shade for those with outdoor access, and using pet-safe sunscreen on vulnerable areas such as the ear tips and nose are all reasonable steps. Some owners apply sunscreen formulations designed for infants, but it is important to avoid products containing zinc oxide or salicylates, both of which are toxic to cats.