Squamous Cell Carcinoma in Pets
If there’s one word that can make a pet parent’s heart drop, it’s ‘cancer.’ Unfortunately, our pets are not spared from this dreaded disease, as much as we would like them to be. Like people, pets can develop many types of cancer, one of which is squamous cell carcinoma (SCC). Keep reading to learn more about SCC in pets and what you can do to help prevent it.
Squamous Cell Carcinoma Basics
Squamous cells are thin, flat, and irregularly-shaped cells that make up the epithelium, which lines the outer layer of the skin and internal organs. These cells have many functions, one of which is protecting underlying tissues. When squamous cells become damaged for such reasons as exposure to ultraviolet radiation or tobacco smoke, they can become cancerous.
Although both dogs and cats can develop SCC, this cancer is much more common in cats than dogs, particularly middle-aged to older cats. There are two main types of SCC in pets: oral and skin.
Oral Squamous Cell Carcinoma
Oral SCC, a locally aggressive cancer, makes up 10% of all feline oral cancers and is the second most common canine oral cancer. It typically affects older pets and has a low survival rate. Although it can be found anywhere in the mouth, such as the tonsils and gums, oral SCC most commonly appears under the tongue. It grows rapidly and frequently invades the jawbone.
In cats, carcinogens like cigarette smoke and flea collar chemicals that land on a cat’s tongue during grooming can cause oral SCC. The exact cause in dogs is not yet known.
Signs of oral SCC include bad breath, difficulty eating, drooling, and oral bleeding and pain. Other symptoms include loose teeth and ulcerated gums. These signs can often be confused with dental disease, so it is essential for veterinarians to perform a thorough oral exam in older pets. Diagnostic procedures are the same for oral SCC as for skin SCC, which can start with labwork, needle aspirate and/or biopsy with histopathology.
Surgery is the standard of treatment for oral SCC. It can be aggressive, with the removal of a portion of the jawbone, nearby lymph nodes, or both, if necessary. Although surgical tumor removal can provide immense pain relief, the tumor’s size and location can sometimes make surgery difficult or even impractical. Non-surgical treatment options include chemotherapy and radiation therapy.
Treatments that do not target the tumor itself, but can help a pet to feel better, include antibiotics, painkillers, and nutritional supplementation.
Prevention strategies include the following:
- Limit sun exposure from 10 am to 2 pm.
- Keep white-haired cats indoors and prevent them from sunbathing in the window.
- Apply a small amount of sunblock to a pet’s exposed skin, such as the tip of the ears and above the nose.. Your veterinarian can recommend a pet-safe sunblock.
- Use UV reflective film on your windows or install a window shade to block UV rays.
- Take your pet to your veterinarian for regular wellness exams.
Oral SCC: Elizabeth & Lola’s Story
“My 8 year-old dachsund-Jack Russell mix was diagnosed with squamous cell cancer of the tonsils,” begins pet parent Elizabeth. “When I brought her to the vet, she had lost weight, had no bark, and seemed to have difficulty eating. The vet found and removed the tumor, but warned me that this is an extremely aggressive form of cancer and that it had most likely already metastasized to her lymph nodes.” Elizabeth was referred to an oncologist, who discovered more lesions in Lola’s lung. They recommended palliative radiation and sadly, gave Lola only 3 months to live.
“I could not just let her die,” says Elizabeth. “So I read all the veterinary and animal literature I could find on what deters cancer cells in animals. The finding that stood out to me was cruciferous vegetables, like broccoli, kale, and Brussel sprouts, have been found to inhibit cancer cells in research on animals.” Elizabeth dived deeper and changed her dog’s diet: “She is a very picky eater, but likes Brussel sprouts, as long as they have butter in them. Also a diet low in carbs, high in protein and with healthy fats was found to be helpful! She has been eating Brussel sprouts with olive oil and a little butter every day, as well as chicken breast. I’d like to get some other fruits and veggies into her, but she won’t eat them.”
While vets and pet parents alike will tell you that cancer is a daunting diagnosis and that it is truly hit-or-miss with alternative solutions, Elizabeth has had success with Lola’s diet. “It is now 3 months post diagnosis. She has regained her weight and her bark, and to all appearances is symptom free, active, and happy. It’s too early to know if she will be a survivor, but I am sharing this in case anyone else’s dog is in a similar position. So far, she is defying the odds. By the way, she may be the cutest and most wonderful dog on this earth— an unbiased opinion.” Lola’s claims have totaled $2,919 and Elizabeth has been reimbursed $2,135 (90% reimbursement rate; $250 deductible). Please note that cancer claims were sandwiched between unrelated claims that may skew the totals.
Skin Squamous Cell Carcinoma (SCC)
Skin SCC is the fourth most common feline skin cancer and makes up about 5% of all canine skin cancers. Excessive sun exposure is the most common cause. By far, white-haired cats are most susceptible to skin SCC and often develop tumor lesions on the temples, eyelids, tip of the nose, and outer tips of the ears. Dogs with sparse hair and lightly pigmented skin and fur (e.g., white Bull Terriers) are also susceptible. Interestingly, in some dogs, skin SCC can target the nailbeds.
Skin SCC typically affects older cats, but both dogs and cats of any breed and age can develop this cancer, depending on their amount of sun exposure and lack of skin pigmentation.
In the early stages, skin SCC doesn’t even look like a tumor. Instead, you might notice a small, solitary skin lesion that looks a little dry, flaky, and ulcerated. Often, these signs can be mistaken for other skin diseases, such as allergies or parasites. As time goes on, the lesion grows, becomes bumpy, develops hard and irregular borders, and causes skin swelling.
Skin SCC rarely spreads beyond its original tumor site, but it can spread to nearby lymph nodes and possibly the lungs. It can also recur in the same spot.
Diagnosing skin SCC is done via a skin biopsy, which will show cancerous squamous cells. Other diagnostic tools include a blood sample, chest x-ray, and lymph node analysis to devise an optimal treatment plan.
Skin SCC is primarily treated with aggressive surgical removal of the lesion and at least a portion of the affected area to ensure removal of all tumor tissue. Other treatments include radiation therapy, cryotherapy (freezing), and chemotherapy.
Bringing it Together
Squamous cell carcinoma is an aggressive cancer in pets. Pay close attention to your pet’s skin, particularly if you have a white-haired cat, and take your pet to your veterinarian if you notice any strange bumps on the skin or oral problems. The optimal treatment plan will depend on the tumor’s size and disease progression.
Content provided by JoAnna Pendergrass, DVM. Dr. Pendergrass is owner and founder of JPen Communications, a medical communications company specializing in consumer education.
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