Cutaneous Squamous Cell Carcinoma in Cats
The epidermis, or skin, consists of several layers. The outer layer is made up of scale like cells called the squamous epithelium. This layer of tissue covers the surface of much of the body, and lines the cavities of the body. A squamous cell carcinoma is a type of cancer that originates in the squamous epithelium. It may appear to be a white plaque, or a raised bump on the skin. Often the raised mass will necrotize in the center and ulcerate, with occasional bleeding.
As carcinomas are characteristically malignant and particularly invasive, it is essential to have this form of skin cancer diagnosed and treated without delay. Cutaneous squamous cell carcinomas are typically fast growing tumors that get bigger with time and resist healing. Some cats can get as many as thirty sores on their skin, a condition called Bowen’s disease. Both types of squamous cell carcinoma can metastasize to other organs. If the ulcers are diagnosed before they have had an opportunity to become malignant, this condition may be treated effectively in some cases.
Squamous cell carcinomas are seen more in cats that live at high altitudes and in cats that spend a lot of time in the sun. White cats and light colored cats are more likely to get these tumors than other kinds of cats. This kind of cancer is most commonly seen in older cats.
Symptoms and Types
- A crusty or bleeding sore on the skin that does not go away with antibiotics or creams
- Sores that do not heal for several months
- Sores in areas where the hair is white or light colored
- Bowen’s Disease
- Skin that changes color and develops an ulcer in the center
- Hair in the sore falls out easily
- Dried, crusty material on the hair near the sore
- As many as 30 sores on the head, neck and shoulders
- Growths or Tumors
- White colored growth
- Growths in areas where hair is white and skin is light colored
- Sores or growths may be found anywhere
- The most common locations are the front of the nose (nasal planum), eyelids, lips, and ear tips
- Long term exposure to sunlight/UV rays
You will need to give your veterinarian a thorough history of your cat's health, onset of symptoms, and possible incidents that might have precipitated this condition, such as a recent fight that might have led to skin injuries, or a flea infestation that would have left open sores from vigorous scratching. Once this history has been detailed, your veterinarian will conduct a thorough physical examination on the cat, paying close attention to any growths on the skin or any sores that have not healed in several months. Your cat's lymph nodes will be palpated to determine if they are swollen, an indication that the body is fighting an invasive disease or infection, and a sample of lymph fluid will be taken for laboratory analysis. The presence of cancerous cells in the lymph glands will be indicative of metastasis through the body. Basic laboratory tests include a complete blood count and biochemical profile to confirm that your cat's organs are functioning normally.
Because carcinomas are characteristically malignant and metastasize quickly, your veterinarian may also order x-ray images of your cat's chest and abdomen so that a visual inspection can be made of the lungs and organs. Likewise, if your cat has a tumor on one of its legs, your veterinarian will want to take x-rays of the leg to see if the tumor has spread to the bone underneath it.
Standard biopsies will be taken of the growth or sore. This is the best way of determining exactly what kind of tumor your cat has.
The course of treatment will depend on how large your cat's tumor is and how many tumors there are. In some cases, when sores are diagnosed before they become cancerous, they can be treated with topical medication.
If your cat only has one small tumor that has not spread to other organs, it may be removed by cryosurgery - freezing technique, or with a special type of light therapy called photodynamic therapy. It may also be surgically removed.
If your cat has a large tumor, it will be treated with surgery. During surgery, the tumor and a lot of the tissue surrounding it will be removed to ensure that all of the caner cells are removed. In some cases, so much tissue may be removed during surgery that skin will need to be taken from another area of the body and used to cover the area where the tumor was, a technique called skin grafting.
Some cases will result in a more severe removal of tissue. For example, tumors that are on the toes require amputation of the affected toe, and tumors on the nose will require a partial removal of the nose. If the tumor is found on the ear, part of the ear will be removed. These types of surgeries will result in a cosmetically different appearance for your cat, but otherwise, cats recover well from these surgeries.
If the tumor cannot be completely removed, your veterinarian may recommend radiation or chemotherapy after surgery. Sometimes, when surgery is impractical, chemotherapy and radiation are used solely to treat tumors. In this case, the chemical treatment will keep the tumor from growing as quickly and help to make your cat more comfortable.
Living and Management
After surgery, you should expect your cat to feel sore. Your veterinarian will give you pain medication for your cat to help minimize discomfort. Use pain medications with caution; one of the most preventable accidents with pets is overdose of medication. Follow all directions carefully. You will need to limit your cat's activity while it heals, setting aside a quiet place for it to rest, away from household activity, children, and other pets. You might consider cage rest for your cat, to limit its physical activity. Your veterinarian will tell you when it is safe for your cat to move about again.
It is important to monitor your cat's food and water intake while it is recovering. If your cat does not feel up to eating, you may need to use a feeding tube so that it is getting all of the nutrition it needs to completely recover. Your veterinarian will show you how to use the feeding tube correctly, and will assist you in setting up a feeding schedule. While your cat is in the process of healing, you may set the litter box up closer to where your cat rests, and make it so that it is easy to get in and out of the box.
If you are treating your cat with a topical (external) medication for its sores, it is important to follow all of your veterinarian’s instructions.
After your cat has recovered, your veterinarian will set up a schedule for regular progress checks. Recurrence is possible, so your doctor will check for any new tumors, and x-rays of the chest and abdomen will be taken to see if there are any new tumors in the lungs or internal organs.
A full recovery will be dependent on the size and location of the tumor.
Limit the amount of time your cat spends in the sun, especially between the hours of 10:00 am and 2:00 pm, when the sun is at its highest and the rays most damaging. If your cat spends a lot of time on the window sill during the day, you might consider placing a window shade or reflector over the glass to block UV rays. If you must allow your cat outdoors during daylight hours, apply sunscreen to your cat's ears and nose before it goes out in the sun. In some cases, tattoos can be applied to light colored skin as a permanent sunscreen. If you should notice any new sores or tumors, take your cat to the veterinarian as soon as possible so that it can be treated immediately.