Squamous Cell Carcinoma in Dogs​: An In-Depth Guide

Squamous cell carcinoma (SCC) is a type of cancer that commonly affects the skin and mucous membranes of dogs. While SCC can be found in various parts of the body, its presence in dogs is most often seen in the skin, especially in areas that are regularly exposed to sunlight. As with any cancer, early detection and treatment are vital in improving a dog’s prognosis and life expectancy. This article will explore the causes, symptoms, diagnosis, treatment options, and life expectancy of dogs with squamous cell carcinoma. We will also address the impact of SCC on dogs’ health and offer useful tips for managing this condition.

What is Squamous Cell Carcinoma in Dogs?

Squamous cell carcinoma is a malignant tumor originating from squamous cells, which are flat cells found in the skin and mucous membranes. SCC is one of the most common skin cancers in dogs, particularly in breeds with light-colored or thin coats that have a higher risk of sunburn. The cancer may develop in areas such as the nose, ears, eyelids, mouth, or other regions that are exposed to ultraviolet (UV) radiation from the sun.

Types of Squamous Cell Carcinoma in Dogs

Squamous cell carcinoma can develop in several parts of a dog’s body. The most common types are:

1. Cutaneous Squamous Cell Carcinoma: This type affects the skin, often appearing as a raised, ulcerated lesion or a firm, scaly growth. It typically develops in sun-exposed areas, such as the face, ears, and belly.

2. Oral Squamous Cell Carcinoma: This form occurs in the mouth and can be difficult to detect because it often presents as an ulcer, swelling, or a growth in the dog’s mouth. It may be accompanied by difficulty eating or bad breath.
   
   

3. Nasal Squamous Cell Carcinoma: This form affects the nose and nasal passages. It often causes nasal discharge, breathing difficulties, and sneezing.

4. Subungual Squamous Cell Carcinoma: This type affects the nail beds, causing swelling, pain, and lameness.

Squamous Cell Carcinoma in Dogs: Symptoms to Watch For

Recognizing the signs of squamous cell carcinoma in dogs can be challenging, as symptoms vary depending on the location and severity of the tumor. However, common symptoms include:

1. Skin Growths

The most common sign of SCC in dogs is the appearance of abnormal skin growths. These growths can appear as raised, firm masses, often with scaly, crusted, or ulcerated surfaces. They may start small but can grow over time.

2. Pain or Sensitivity

If the tumor is in a sensitive area, such as the ear, paw, or mouth, the dog may exhibit signs of pain, such as limping, whining, or sensitivity when touched.

3. Abnormal Bleeding or Discharge

A squamous cell carcinoma tumor can bleed, ooze, or produce pus. In some cases, you may notice a foul odor, especially if the tumor is in the mouth or ears.

4. Changes in Appetite or Difficulty Eating

When SCC affects the mouth or throat, it can make chewing painful. This leads to a loss of appetite, weight loss, and difficulty eating, which are common symptoms in dogs with oral squamous cell carcinoma.

5. Swelling and Lameness

For SCC that affects the paws or nail beds, the dog may have noticeable swelling or lameness. The affected paw might become red and inflamed, and the dog may limp or avoid using it.

6. Respiratory Issues

In cases where SCC affects the nasal passages, you may notice breathing difficulties, snoring, nasal discharge, or sneezing. Tumors in this area can obstruct the airway and cause discomfort.

What Causes Squamous Cell Carcinoma in Dogs?

While the exact cause of SCC in dogs is not fully understood, several factors increase the risk of developing this cancer:

1. Sun Exposure

Dogs with light-colored or thin coats are more prone to SCC, particularly if they spend a lot of time outdoors. UV radiation from the sun can damage the skin cells, leading to the development of skin cancers like SCC.

2. Age

Squamous cell carcinoma is more common in older dogs, especially those over the age of 8 years. The risk of developing SCC increases as the dog ages, possibly due to a weakened immune system or cumulative sun exposure.

3. Genetics and Breed

Certain dog breeds, such as Boxers, Cocker Spaniels, and Dachshunds, are more prone to SCC. Genetic factors may predispose these breeds to developing skin and oral cancers.

4. Chronic Skin Infections or Irritation

Chronic irritation or injury to the skin, such as repeated sunburn, flea infestations, or skin infections, can lead to the development of squamous cell carcinoma over time.
Also Read: Bacterial Skin Infections in Dogs

How is Squamous Cell Carcinoma Diagnosed in Dogs?

If a dog presents symptoms consistent with squamous cell carcinoma, a veterinarian will perform a thorough examination, including a biopsy and imaging tests, to confirm the diagnosis.

1. Physical Examination

The veterinarian will examine the dog’s skin and mucous membranes, looking for abnormal growths or signs of inflammation. In some cases, a mass may be palpated in the mouth, ears, or paws.

2. Biopsy

A biopsy involves taking a small sample of the suspected tumor for laboratory analysis. This helps determine whether the growth is cancerous and the specific type of cancer.

3. X-Rays or Ultrasound

If the tumor is located in the mouth, nose, or internal organs, imaging tests such as X-rays or ultrasounds may be used to assess the extent of the tumor and whether it has spread to other areas of the body.

4. Blood Tests

Blood tests can help determine the overall health of the dog and identify any underlying issues that may affect treatment options.

Squamous Cell Carcinoma in Dogs: Treatment Options

Treatment for squamous cell carcinoma in dogs depends on the location, size, and stage of the tumor. The goal is to remove or shrink the tumor and prevent its spread.

Common treatment options include:

1. Surgery

Surgical removal of the tumor is the most common treatment for squamous cell carcinoma, particularly for localized skin tumors. The veterinarian will excise the tumor along with a margin of healthy tissue to reduce the risk of recurrence. For oral tumors, surgery may be more challenging due to the location, and complete removal might not be possible.

2. Radiation Therapy

In cases where surgery is not an option or if the tumor cannot be entirely removed, radiation therapy may be used to shrink the tumor and kill cancerous cells. Radiation is particularly effective for oral and nasal SCC.

3. Chemotherapy

Chemotherapy is typically used when the cancer has spread or if surgery and radiation are not effective. Chemotherapy can help to slow the growth of the cancer, although it is less commonly used for SCC in dogs than in other cancers.

4. Cryotherapy

Cryotherapy involves freezing the tumor with liquid nitrogen. This method is typically used for superficial skin SCC that is difficult to surgically remove.

5. Immunotherapy

In some cases, immunotherapy may be used to boost the dog’s immune system, helping it fight the cancer. This treatment is still in experimental stages for SCC in dogs.

Squamous Cell Carcinoma in Dogs: Life Expectancy

The life expectancy of a dog diagnosed with squamous cell carcinoma depends on several factors, including the tumor's location, whether it has spread, and how early it was detected. Early-stage SCC confined to the skin can often be treated successfully with surgery, offering a favorable prognosis with a good chance of complete recovery. However, SCC in more critical areas, such as the mouth or nose, may have a more guarded prognosis due to the difficulty of complete removal and the potential for metastasis.

For dogs with untreated or advanced SCC, the prognosis is less favorable. It is crucial to follow up with your veterinarian for regular check-ups and additional treatments, as SCC may recur even after treatment.

Prevention and Management of Squamous Cell Carcinoma in Dogs

While it may not be possible to prevent squamous cell carcinoma entirely, there are steps that pet owners can take to reduce their dog’s risk:

1. Limit Sun Exposure: Keep dogs with light-colored fur indoors during peak sun hours and apply pet-safe sunscreen to exposed areas, such as the nose and ears.

2. Regular Vet Check-ups: Regular vet visits can help identify skin abnormalities and other symptoms early.

3. Healthy Diet and Lifestyle: Maintaining a healthy lifestyle, including proper nutrition and weight management, can help strengthen the immune system and reduce the risk of cancer.

FAQ

1. What is squamous cell carcinoma in dogs?

Squamous cell carcinoma is a type of cancer that affects the skin and mucous membranes of dogs. It can occur in areas such as the skin, mouth, ears, and nose, often due to sun exposure.

2. What are the symptoms of squamous cell carcinoma in dogs?

Common symptoms include abnormal skin growths, bleeding, pain, difficulty eating, swelling, lameness, and respiratory issues. Tumors may also cause foul odors or discharge.

3. How is squamous cell carcinoma diagnosed in dogs?

Diagnosis typically involves a physical examination, biopsy, X-rays, and blood tests. Imaging helps determine the extent of the tumor.

4. How is squamous cell carcinoma in dogs treated?

Treatment options include surgery to remove the tumor, radiation therapy, chemotherapy, cryotherapy, and in some cases, immunotherapy.

5. What is the life expectancy of a dog with squamous cell carcinoma?

Life expectancy depends on the tumor’s location, stage, and whether it has spread. Early detection and treatment can result in a good prognosis, especially for skin SCC.

6. Can squamous cell carcinoma in dogs be prevented?

While prevention isn’t always possible, limiting sun exposure and having regular veterinary check-ups can help reduce the risk of developing SCC.

By understanding squamous cell carcinoma in dogs and recognizing the early signs, pet owners can take proactive steps to manage the condition and improve their dog’s quality of life. Early diagnosis and treatment are key to extending life expectancy and minimizing discomfort.