고양이 편평세포암 종양학 자주 묻는 질문 Q&A — 보호자가 꼭 알아야 할 핵심

What is Feline Squamous Cell Carcinoma? — What Symptoms Should Raise Suspicion?

Oncology/CancerQ&AMeongsiljang Veterinary Advisory Board

Feline squamous cell carcinoma is a malignant tumor that develops on the skin or mucous membranes, and early detection along with appropriate treatment significantly impacts survival rates. We’ve compiled the essential information every pet owner should know.

What is Feline Squamous Cell Carcinoma?

Squamous cell carcinoma lesion on the tip of a cat's ear

Feline squamous cell carcinoma is a malignant tumor that arises from the skin’s keratinocytes. It commonly develops in sun-exposed, sparsely haired areas such as the ear tips (pinnae), nose (nasal planum), preauricular region, eyelids, and lips. Early detection is crucial, as prognosis improves significantly when small, superficial tumors are treated promptly.

Recurring skin damage: Sun-exposed areas may show persistent peeling, crusting, or scaling.

Nodule or ulcer formation: Lesions often begin with crusting or scaling, then progress to proliferative or ulcerative changes.

Easy bleeding: The affected tissue is fragile and bleeds easily with minor irritation.

Multiple lesions: Approximately 45% of affected cats develop lesions in more than one location.

When small, superficial lesions are completely removed at an early stage, the prognosis is generally favorable.

Why Does Feline Squamous Cell Carcinoma Develop in Cats?

Feline squamous cell carcinoma is primarily linked to chronic ultraviolet (UV) exposure as a key risk factor. It occurs more frequently in cats with prolonged sun exposure, particularly those with white coats.

UV Exposure: Prolonged, chronic exposure to sunlight damages the skin and increases the risk of developing squamous cell carcinoma.

Lack of Pigmentation: White-coated cats have less pigment (melanin) in their skin and nose, making them more vulnerable to UV rays. Consequently, white cats face a significantly higher risk of developing squamous cell carcinoma in the ears compared to pigmented cats.

Advanced Age: This cancer is more commonly seen in older cats, typically around the average age of 11 years.

Pre-existing Actinic Keratosis: Actinic keratosis, caused by chronic UV damage, can progress into squamous cell carcinoma.

Avoiding sunlight is the cornerstone of prevention.

White cats should avoid direct sunlight.

What Are the Early Symptoms?

The early signs of feline squamous cell carcinoma can appear mild. However, ignoring them can lead to worsening conditions, so close attention is necessary.

Crusts and scales: Initially, the skin may develop repeated crusting and flaking, resembling scales.

Thick nodules and ulcers: Small lesions can gradually grow into proliferative nodules or break down into ulcers.

Easy bleeding: The lesions are prone to breaking down and can bleed easily with minor irritation or scratching.

Flaking like white dandruff: The skin may flake off in white, scale-like patches without hair loss.

Lesions on the ear tips and nose: In white cats, erosions and crusting lesions often develop on the ear tips and nose (nasal planum).

If these symptoms persist for more than two weeks, consult a veterinarian immediately.

Early-stage squamous cell carcinoma lesions in a cat's nose

Signs Requiring Immediate Veterinary Visit

If your cat repeatedly scratches or licks a skin lesion, or if the lesion grows larger and bleeds heavily, you should take them to the vet immediately.

How Is an Accurate Diagnosis Made?

If a suspicious lesion is found, your veterinarian will perform a biopsy to confirm the diagnosis. This step is essential for determining whether the condition is malignant and guiding the treatment plan.

Skin biopsy: A small tissue sample is taken from the lesion and examined under a microscope.

Histological analysis: The shape and structure of the cells are evaluated to determine if the lesion is malignant.

Pathology report: The final diagnosis and the degree of malignancy are documented.

Imaging tests: These help assess how deeply the lesion has invaded and whether it has spread to the lymph nodes.

Biopsies are safe procedures, so there’s no need to worry.

A veterinarian performing a skin biopsy on a cat

What Are the Treatment Options?

Treatment options depend on the location, size, and extent of invasion of the lesion. Early detection of small, superficial lesions generally leads to a favorable prognosis.

Surgical excision: Wide surgical excision is the primary treatment, and complete removal results in a good prognosis.

Cryosurgery: This is the most commonly used method alongside surgery and is practical for use in general practice.

Radiation therapy: Squamous cell carcinoma shows a moderate response to radiation, making it a viable alternative or adjunctive treatment for areas where adequate surgical excision is difficult.

Photodynamic therapy: This has been successfully used to treat early and superficial lesions on the nose (nasal planum).

Chemotherapy: It is not recommended for localized squamous cell carcinoma but may be considered as an adjunctive treatment alongside surgery and radiation for advanced or invasive lesions.

Treatment decisions must always be based on a veterinarian’s diagnosis.

Comparison Table of Treatment Methods

Item	Suitable Cases	Side Effects	Recovery Period
Surgical Removal	When the lesion is small and localized (primary treatment)	Low	1–2 weeks
Radiation Therapy	Sites where adequate surgical resection is difficult (moderate radiosensitivity)	Moderate	2–4 weeks
Chemotherapy	Not recommended for localized lesions; adjunctive therapy for advanced/invasive lesions	High	4–6 weeks
Laser/Photodynamic Therapy	Superficial lesions	Low	Within 1 week

The treatment method is determined by the veterinarian's diagnosis, and wide surgical resection is the primary treatment. Chemotherapy is not recommended for localized squamous cell carcinoma.

Post-Treatment Precautions

Even after treatment, lesions can recur or spread, so regular check-ups and skin care are essential.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

Is feline squamous cell carcinoma treatable?

Yes, the prognosis is generally favorable if small, superficial lesions are completely removed through wide surgical excision at an early stage. If surgery is challenging, radiation therapy can be used as an alternative or adjunct treatment. Early intervention is key.

Can it be prevented with a vaccine?

No, there is currently no vaccine for squamous cell carcinoma. Sun protection and proper skin care are the most effective preventive measures.

Are senior cats at higher risk?

Yes, squamous cell carcinoma is more commonly seen in older cats, typically around the age of 11. Additionally, the risk increases with cumulative chronic exposure to ultraviolet light, so extra care is needed for senior cats.

Should I regularly check my pet’s skin at home?

Yes, please check your pet's ears, nose, and the area around their eyes thoroughly at least once a week. If you notice any changes, it's important to visit the vet right away.

How can I keep my pet out of the sun?

Keep your cat indoors during peak sunlight hours, apply UV-blocking film to windows, or use a cat-specific UV protection spray.

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References

[1] London, C.A. et al. (2009) Tyrosine kinase inhibitors in veterinary medicine. Top Companion Animal Med. 24:106–112.

[2] Rutten, V.P. et al. (2014) Use of surgery and carboplatin in feline malignant mammary gland neoplasms with advanced clinical staging. In Vivo. 28(5):863–866.

[3] Veterinary Surgical Oncology, 2nd Ed. (2006) Chapter on cutaneous neoplasia in cats. Elsevier.