What is feline cutaneous squamous cell carcinoma (FC-SCC)?
FC-SCC is the most common form of skin cancer in cats. It typically develops on areas exposed to the sun, such as the ears, nose, eyelids, and lips. The cancer arises from squamous epithelial cells, causing ulcerated or crusted lesions.
What causes FC-SCC?
The primary cause of FC-SCC is prolonged exposure to ultraviolet (UV) radiation from the sun. UV radiation damages the skin cells, leading to the development of cancer. Light-colored cats or those with sparse fur are especially vulnerable to this type of cancer.
Which cats are most at risk?
Cats at the highest risk of developing FC-SCC include:
- White or light-colored cats
- Cats living in sunny climates
- Cats that spend a lot of time sunbathing
- Older cats (typically over 10 years old)
What are the symptoms of FC-SCC?
Symptoms often start with subtle skin changes, such as redness, crusting, or small sores. As the cancer progresses, these lesions may grow, ulcerate, and become more severe. The most commonly affected areas are:
- The nose
- Ears (pinnae)
- Eyelids
- Lips
How is FC-SCC diagnosed?
A definitive diagnosis of FC-SCC is made through a biopsy of the affected area. Your veterinarian will remove a small sample of tissue to examine under a microscope. Other diagnostic tests, such as imaging and lymph node assessment, may be recommended to check for the spread of the cancer.
Can FC-SCC spread to other parts of the body?
While FC-SCC tends to be slow to metastasize (spread to other parts of the body), it can invade nearby tissues and lymph nodes if left untreated. In advanced cases, it may spread to the lungs.
How is FC-SCC treated?
There are several treatment options for FC-SCC, depending on the location and severity of the cancer. These include:
- Surgical removal: The most common and effective treatment, especially if the cancer is detected early. The goal is to remove the tumor with clear margins to prevent recurrence.
- Cryotherapy: Freezing the cancerous tissue to destroy it, often used for smaller lesions.
- Electrochemotherapy: A combination of chemotherapy and electric pulses to enhance the effectiveness of the treatment.
- Photodynamic therapy: Uses a drug that makes cancer cells sensitive to light, followed by exposure to a specific wavelength of light to kill the cells.
- Radiation therapy: Can be very effective, particularly for small, well-defined tumors but even for larger ones.
What is the prognosis for cats with FC-SCC?
If caught early and treated appropriately, the prognosis for cats with FC-SCC is generally good. Surgery offers the best chance for a cure. However, the prognosis worsens if the cancer is allowed to progress or metastasize.
Can FC-SCC be prevented?
Preventing FC-SCC primarily involves minimizing your cat’s exposure to UV radiation. Some prevention strategies include:
- Keeping cats indoors, especially during peak sunlight hours.
- Using UV-blocking window screens.
- Applying pet-safe sunscreen to vulnerable areas (such as the ears and nose), though some cats may not tolerate this.
What should I do if I notice signs of FC-SCC in my cat?
If you notice any suspicious skin changes, particularly in sun-exposed areas, it’s essential to consult your veterinarian. Early detection is key to successful treatment, and delays can lead to a more complicated prognosis.
Does FC-SCC cause pain or discomfort for cats?
Yes, as FC-SCC lesions grow and ulcerate, they can cause pain and discomfort. Prompt treatment is necessary to alleviate these symptoms and improve the cat’s quality of life.
This FAQ was developed using information from a senior paper authored by Brandy Schaefer (’25), titled “No Fun from the Sun: A Review of Feline Cutaneous Squamous Cell Carcinomas,” submitted on July 18, 2024, under the guidance of Dr. Janean Fidel.
This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian. Washington State University assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.