Malignant Tumor of the Upper Skin Layer in Dogs (Cutaneous Squamous Cell Carcinoma)
- Occurrence: very rare
- Location of disease: Skin/Fur
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Cutaneous squamous cell carcinoma in dogs is a malignant tumor disease that originates from the cells of the squamous epithelium, which forms the outermost layer of the skin.
The most important facts at a glance
Squamous cell carcinomas in dogs develop through uncontrolled growth of malignant cells in the outer skin layer, the epidermis. This type of cancer is caused by genetic mutations that disrupt normal cell division. Although the exact causes are not fully understood, UV radiation, genetic predispositions, and environmental factors are considered risk factors. Certain dog breeds such as Bull Terriers and Beagles are more susceptible. Symptoms include non-healing wounds, crusts, skin nodules, and occasionally weight loss. Diagnosis is made through clinical examination and biopsy, supported by imaging procedures such as X-ray or ultrasound. Treatment varies depending on tumor stage and usually includes surgical removal, radiation therapy, or chemotherapy. Pain management is also important. The prognosis depends on the timing of diagnosis and the possibility of complete tumor removal. Preventive measures include minimizing sun exposure, especially in dogs with light skin or thin fur, as well as regular skin examinations. Research focuses on improving diagnostics, developing new therapeutic approaches such as photodynamic therapy, and investigating genetic factors to develop targeted prevention strategies.
Causes
Squamous cell carcinomas develop when cells in the squamous epithelium of the skin grow uncontrollably and become malignant. These cells are located in the epidermis, the outer layer of skin that protects the body from environmental influences. Normally, skin cells grow and divide in a controlled manner, but genetic mutations can disrupt these processes and lead to tumor formation.
The exact cause of squamous cell carcinomas is not fully understood, but it is believed that multiple factors play a role. A major risk factor is exposure to ultraviolet (UV) radiation, which increases the risk of skin cancer in both humans and animals. Light skin or thin fur can increase a dog’s susceptibility to harmful UV rays.
Additionally, genetic predispositions can influence susceptibility to this type of cancer. Certain breeds such as Bull Terriers, Beagles, and Boxers appear to be more frequently affected. Environmental factors such as exposure to certain chemicals can also increase the risk.
Symptoms
Dogs with squamous cell carcinoma often show visible skin changes. A common sign is the presence of firm, often painless tumors or ulcers that do not heal or recur. These lesions can vary in appearance, from red, scaly patches to firm, raised nodules.
The tumors frequently occur on body areas exposed to the sun, such as the nose, ears, belly, and legs. In dogs with dark fur, the symptoms may be less clearly recognizable, making diagnosis more difficult. In advanced stages, affected dogs may also show signs of discomfort, weight loss, or loss of appetite.
Therapy
Treatment of squamous cell carcinomas in dogs depends on the location, size, and extent of the tumor, as well as the dog’s overall health condition. Surgical removal of the tumor is often the preferred treatment method, especially if the cancer has not yet metastasized. Complete resection with adequate safety margins is crucial to prevent recurrence.
In cases where the tumor cannot be completely removed or when metastases are present, radiation therapy may be considered. This treatment aims to destroy remaining cancer cells and slow tumor growth. Chemotherapy may also be used, especially in more aggressive forms or when the cancer has already spread.
In addition to specific treatments, pain control and support of the dog’s overall well-being are important. This may include the administration of pain relievers and anti-inflammatory medications.
Prognosis and follow-up care
The prognosis for dogs with squamous cell carcinoma depends on various factors, including the stage of the cancer at diagnosis, the possibility of complete surgical removal, and the presence of metastases. Tumors detected early that can be completely removed generally have a better prognosis.
In advanced or metastasized cases, the prognosis may be less favorable. Quality of life and survival time can be improved through palliative treatments and supportive care.
Prevention
Prevention of squamous cell carcinomas in dogs focuses primarily on minimizing sun exposure, especially in dogs with light skin or thin fur. The use of special sunscreens for dogs and avoiding walks in the blazing midday sun can reduce the risk.
Regular skin examinations by the dog owner and veterinarian are important to detect changes early. When choosing dog breeds, consideration of genetic predispositions for certain cancers can be helpful.
Although not all cases of squamous cell carcinomas can be prevented, these measures can reduce the risk and severity of the disease.
Outlook on current research
Research on cutaneous squamous cell carcinoma in dogs is a dynamic research field that continuously provides new insights. A focus of current research is on improving diagnostic techniques to enable early detection and treatment of this form of skin cancer. Modern imaging procedures such as advanced ultrasound and MRI techniques are being studied to evaluate their effectiveness in detecting tumors in early stages.
Another area of research focuses on the genetic factors that contribute to the development of squamous cell carcinomas. Scientists are investigating genetic markers associated with an increased risk for this form of skin cancer to potentially develop targeted prevention strategies. These investigations could lead in the long term to genetic tests that make it possible to identify dogs at increased risk early.
Additionally, researchers are working on developing new therapeutic approaches. These include both surgical and non-surgical treatment methods. Photodynamic therapy (PDT), in which light-sensitive substances are injected into the tumor and then irradiated with light, shows promising results. This method could represent a minimally invasive alternative to conventional surgery.
In pharmacology, research is being conducted on medications that specifically target the molecular mechanisms of squamous cell carcinoma. The goal is to develop drugs that inhibit tumor development without damaging healthy cells. Animal models and cell cultures are used to test the efficacy and safety of new active substances.
An exciting field is immunotherapy, in which the body’s own immune system is activated to fight cancer cells. This involves investigating how immune cells can be modified to specifically attack tumor cells. Initial studies show that this method has the potential to treat particularly aggressive tumor forms.
The significance of environmental factors such as UV radiation and chemicals that can contribute to the development of skin cancer is also being intensively researched. With an understanding of these influences, scientists hope to develop preventive measures that reduce the risk of skin cancer in dogs.
In summary, research on cutaneous squamous cell carcinomas in dogs aims to continuously improve diagnosis, prevention, and treatment. Advances in personalized medicine could enable individually tailored treatment plans in the future that are adapted to the specific needs and genetic profiles of each dog.
Frequently Asked Questions (FAQs)
1. What is cutaneous squamous cell carcinoma in dogs?
2. What symptoms indicate squamous cell carcinoma?
3. How is squamous cell carcinoma diagnosed?
4. What Treatment Options are Available?
5. What is the prognosis for dogs with squamous cell carcinoma?
6. Are there specific risk factors for this type of skin cancer?
7. Can squamous cell carcinomas in dogs be prevented?
8. Are squamous cell carcinomas in dogs contagious?
9. Can other animals or humans be affected by a dog with this disease?
10. What should I do if I am concerned that my dog has squamous cell carcinoma?
Literature
- Willcox, J. L., Marks, S. L., Ueda, Y., & Skorupski, K. A. (2019). Clinical features and outcome of dermal squamous cell carcinoma in 193 dogs (1987–2017). Veterinary and Comparative Oncology, 17(2), 130–138. https://doi.org/10.1111/vco.12461
- Dos Santos, A., Lamego, É. C., Eisenhardt, L. M., de Vargas, I., Flores, M. M., Fighera, R. A., & Kommers, G. D. (2023). Prevalence and anatomopathological characterization of cutaneous squamous cell carcinomas with regional and distant metastases in dogs and cats: 20 cases (1985–2020). Veterinary and Comparative Oncology, 21(2), 291–301. https://doi.org/10.1111/vco.12887
- de Castro Cunha, R. M., Lavalle, G. E., Nunes, F. C., Oliveira, A. R., Santos, R. L., & Araújo, R. B. (2023). Canine squamous cell carcinoma: Electrochemotherapy association with surgery and correlation with overall survival. Veterinary and Comparative Oncology, 21(2), 240–254. https://doi.org/10.1111/vco.12882
- Dos Anjos, D. S., Bueno, C., Magalhães, L. F., Santos, B. S., de Freitas, L. M., da Silva, V. H., Rocha, N. S., & Brunner, C. H. M. (2019). Electrochemotherapy induces tumor regression and decreases the proliferative index in canine cutaneous squamous cell carcinoma. Scientific Reports, 9, Article 15819. https://doi.org/10.1038/s41598-019-52461-6
- Cerezo-Echevarria, A., Grassinger, J. M., Beitzinger, C., Klopfleisch, R., & Aupperle-Lellbach, H. (2021). Evaluating the histologic grade of digital squamous cell carcinomas in dogs with dark and light haircoat: A comparative study of the invasive front and tumor cell budding systems. Veterinary Sciences, 8(1), Article 3. https://doi.org/10.3390/vetsci8010003
- Tellado, M., Mir, L. M., & Maglietti, F. (2022). Veterinary guidelines for electrochemotherapy of superficial tumors. Frontiers in Veterinary Science, 9, Article 868989. https://doi.org/10.3389/fvets.2022.868989
- Munday, J. S., Thomson, N. A., & Luff, J. A. (2017). Papillomaviruses in dogs and cats. The Veterinary Journal, 225, 23–31. https://doi.org/10.1016/j.tvjl.2017.04.018