Squamous Cell Carcinoma In Dogs

Squamous Cell Carcinoma (SCC) is the second most common malignant neoplasm in dogs that can develop in a variety of locations. They are invasive, the unregulated proliferation of epidermal prickle–squamous cell layers that also show keratinocytic differentiation.

The biological behavior and appearance of this tumor are variable and nonspecific. German pathologist Krompecher 1902 first distinguished SCC from basal cell carcinoma. The terms ‘epidermoid carcinoma,’ ‘squamous cell epithelioma,’ ‘epithelioma spinocellular,’ ‘spinalioma’ and ‘prickle cell epithelioma’ have all been used in medical circles, but ‘squamous cell carcinoma’ is the most commonly used terminology.

Approximately, 25% of SCC in dogs is diagnosed in the oral cavity. They can arise virtually from any surface in the oral cavity, including the tongue, gingiva, buccal mucosa, tonsils, lips, and pharynx. Oral neoplasms typically exhibit a high rate of metastasis to local lymph nodes and the lungs. In general, most dogs with SCC will go on to develop the metastatic disease even with complete removal of the local oral tumor. SCC should be properly differentiated from other malignant tumors of the oral cavity (e.g., melanoma, fibrosarcoma)

They are usually seen in small breeds and older dogs’ (of more than10 years). In dogs, almost 5-10 % of cutaneous neoplasms are SCC. The common sites include the perineum, scrotum, nasal planum, and legs.

1. Oral SCC:

• Loose teeth
• Increased drooling
• Dysphagia
• Facial swelling
• Weight loss
• Bleeding from the oral cavity
• Halitosis
• Inability to eat/ Dropping food from the mouth

2. Cutaneous SCC:

• Firm, red nodules or slightly raised area on the old scar, darker speckles
• Flat sore on lip/ rough, scaly patch on your lips
• Genitals, anus: wartlike sores
• Itching/ painful
• Coloration can vary from grey, brown, red, or black

3. Ocular (Eye) SCC:

• White painless growth in eyes
• Specks / dark-colored flashes/floaters in the eye
• Eye redness
• Cloudy/ hazy eyes
• Darkening of the iris
• Swelling in or around your dog’s eye
• Twitching muscles around the eyes

4. Subungual (Nail Bed) SCC:

• The wart-like appearance of the nail bed
• Black /brown streaks in the nail
• Ulceration and nodularity
• Nail plate discoloration
• Bleeding, discharge, or swelling of the affected toe
• Onycholysis
• Licking/ chewing at the affected area

The symptoms of metastasized SCC to other organs such as lungs or liver may include:

• Difficulty chewing or swallowing
• Coughing
• Vomiting
• Swelling of the abdomen with fluid
• Limping or signs of pain when walking
• Weakness
• Lack of appetite

Treatment regimen for Squamous cell carcinoma is intended for controlling the primary tumor and dealing with the concern for metastasis.

Surgery, chemotherapy, radiation, or a combination of these treatments are usually employed.

For control of primary tumors, the most potent options are surgery and/or radiation therapy.

SCC’s are sometimes resistant to chemotherapy, so there are typically no long-lasting responses. Though, Chemotherapy is usually reserved as a rescue choice for neoplasms that seems to recur or metastasize.

Due to the location of some tumors, the full surgical removal of the tumor is typically not possible.

However, pet owners should understand that remissions of tumors will happen after some time.

The recommendations by medical oncologists may vary for each dog, so follow the suitable monitoring schedule given for your pet.

As with any tumor, the prognosis is dependent on its location, extent of the disease, and the treatment chosen.

Discuss home treatments with your vet and decide the most fitting foods for your dog.

Calculate your dog's daily calorie intake and find out the right amount - 70 x (Ideal Body Weight in kg)^0.75.

Prevention is not possible for Squamous cell carcinoma as the causes in dogs is varied. Treatment and survival rates differ based on the stage and histologic subtype of cancer.

Clinical stage I disease: Median survival time is 20 months (when properly treated).

Clinical stage II disease: Median survival time of 12-14 months.

Dogs that cross the second clinical stage have the worse prognosis, with median survival times reported as < 3 months, even after treatment.

Keeshond, Schnauzer, Basset Hound, Collie, Dalmatian, Bull Terrier, Beagle, Young Dogs, Adult Dogs, Chow Chow, Cocker Spaniel, Dachshund, English Springer Spaniel, Gordon Setter, Golden Retriever, Labrador Retriever, Miniature Poodle, Shetland Sheepdog, Rottweiler, Standard Poodle, Scottish Terrier, Mix Dog Breeds

1. Causes:

• SCC risk generally increases with age – SCC means age is 6 -11 years old
• Outdoor dogs are more at risk- Exposure to sunlight
• Papillomavirus
• Dogs with dark-colored coats
• Large breed dogs
• Short haired dogs

2. Types:

Oral SCC:

Generally, 25% of SCC we see in dogs will be diagnosed in the oral cavity (including the hard or soft palate, tongue, gingiva, and lip).

Subungual SCC:

The second most common location of SCC is Nailbed or subungual crest. Almost 25% of SCC in dogs are digital (toe) tumors and occur frequently as a solitary lesions.

Dermal or Cutaneous SCC:

This newly described variant of SCC is limited to the dermis, epidermis, and/or subcutaneous (hypodermis) fat.

Ocular SCC:

These subtype of tumors are uncommon and affects the dog’s eye as eyelids, conjunctival masses, limbal melanocytes, and uveal tumors.

3. Diagnosis:

• Blood tests
• Tissue biopsy
• Abdominal radiographs, ultrasound, or CT scan
• MRI scan/ PET scan
• CT scan lymphangiography
• Sentinel lymph Node Biopsy

4. Mortality:

Canine oral SCC has average (median) survival times of 1- 3 months without treatment. The mortality rate of SCC is higher than that of other cancers. Most commonly, affected dogs are euthanized compassionately because of the local effects of the tumor, pain, and poor quality of life.

5. Prognosis:

Prognosis and response are directly proportional to the extent of the spread. The long-term prognosis of SCC is usually guarded as treatment is based on the location malignancy has developed.

Unfortunately, most dog's responses to treatment in negative. These are the cases of euthanasia if their quality of life is severely affected.

Relapses may happen and this is totally dependent on the severity of the disease and metastasis.

Emergency — Immediate Veterinary Assistance Needed

• Bleeding from the oral cavity
• Sudden collapse
• Bleeding, discharge, or Swelling of the affected toe

• Cancer-fighting foods: Low carb, Organic, high-protein, and cruciferous foods.
• In general, all foods should be fresh, highly palatable, and easily digested and nutrients should be highly bioavailable.

Some of the most popular include:

• Cruciferous vegetables, such as Cabbage, collards, broccoli, cauliflower, and kale
• Fresh vegetables/fruit (carrots, banana, green beans, apple, orange)
• Protein, such as lean beef, chicken, fish, turkey
• Antioxidant berries such as blueberries, Strawberries
• Omega 3 fatty acid foods (flaxseeds, avocados, salmon, Sardines, Mackerel, Herring, etc)

The canine SCC prognosis for recovery is highly fickle and depends on several factors, including the stage, histologic subtype, response to treatment, and severity of metastasis.

Regardless of treatment, the long-term prognosis is generally poor. Usually, dogs with SCC may live 3 months without treatment, and the median survival time improves a little to 3-20 months with appropriate treatment.