Tumors of the pleura, peritoneum, and other soft tissues in dogs (Mesothelioma)
- Occurrence: very rare
- Location of disease: Abdomen/pelvis, Chest
When to visit the vet?
Non-urgent see a veterinarian within 2–3 days
If the condition worsens / symptoms persist, consult a veterinarian.
Definition
Mesothelioma is a rare, malignant tumor that occurs in dogs, primarily affecting the pleura, peritoneum, or other soft tissues.
BASICS/CAUSES:
Mesotheliomas arise from mesothelial cells that line the serous cavities of the body, such as the pleura and peritoneum. These cells provide a protective, lubricating surface that facilitates organ movement. Mesothelioma is an aggressive tumor form characterized by uncontrolled cell growth in these tissues.
The exact causes for the occurrence of mesotheliomas in dogs are not yet fully understood. However, there are indications that environmental factors could play a role. In humans, asbestos exposure is a known cause of mesotheliomas, and similar connections have been suspected in dogs.
Genetic factors could also play a role by influencing the susceptibility to the development of Tumors. An accumulation of mesothelioma cases has been observed in certain dog breeds, which could indicate a genetic predisposition.
Another possible trigger is chronic Inflammatory conditions in the chest or abdominal cavity, which could increase the risk of mesothelioma development. These Inflammatory conditions could be caused by repeated injuries or infections.
The most important facts at a glance
Mesotheliomas in dogs are Tumors that affect the pleura or peritoneum. The exact cause is not well understood, but unlike in humans, there is no clear connection with asbestos. Symptoms can include reduced exercise tolerance, Abdominal pain, loss of appetite, and respiratory problems. Occasionally, Respiratory distress or fluid accumulations in the abdominal cavity occur. Diagnosis is made through clinical examinations and imaging such as X-ray or ultrasound; often a biopsy is necessary to confirm the diagnosis. Treatment requires a multimodal approach that may include surgery, radiation therapy, and chemotherapy, with the focus on alleviating symptoms and improving quality of life. Early diagnosis can improve the prognosis, but survival time is often limited. Since the causes are unclear, specific prevention strategies are lacking, although minimizing exposure to carcinogenic substances is recommended. Research focuses on developing better diagnostic methods and new therapies, such as immunotherapy. Advances in imaging and the identification of biomarkers could improve early detection. An interdisciplinary approach is crucial to improving the quality of life of affected dogs and developing new treatment options.
Causes
- The exact cause of mesotheliomas is not well understood in dogs. In humans, an association with asbestos exposure is discussed, but for dogs, this is less clearly defined.
Symptoms
The symptoms of mesothelioma in dogs can vary depending on which tissue is affected. However, general symptoms are often nonspecific and pose a challenge in diagnosis.
In mesothelioma of the pleura, Respiratory distress, Cough, or reduced exercise tolerance may occur, as fluid can accumulate in the chest cavity, known as pleural effusion.
Mesothelioma of the peritoneum can lead to symptoms such as Abdominal pain, Vomiting, Diarrhea, or a bloated abdomen. Here too, fluid can accumulate, which is known as ascites.
In advanced stages, Weight loss, loss of appetite, and general weakness may occur. These symptoms are often the result of the metabolic burden from the tumor and associated complications.
Therapy
The treatment of mesotheliomas in dogs is complex and often requires a multimodal approach. Surgical interventions may be considered to remove the tumor or alleviate symptoms, especially if the tumor is localized.
Radiation therapy can be used in some cases to reduce tumor mass and alleviate symptoms. However, effectiveness depends on the location and extent of the tumor.
Chemotherapy can also be an option, either as a standalone treatment or in combination with surgery and radiation therapy. Some chemotherapeutic agents can slow tumor growth but must be carefully monitored for side effects.
Palliative care, which focuses on alleviating symptoms and improving quality of life, is often an important component of the treatment plan. This includes the treatment of pleural effusions or ascites as well as the prescription of pain medications.
Prognosis and follow-up care
The prognosis for dogs with mesothelioma is generally guarded to poor, as it is an aggressive tumor type that is often detected late. Survival time depends on many factors, including tumor location, extent at diagnosis, and the chosen treatment.
Dogs that are diagnosed early and treated comprehensively may have a better prognosis, but median survival time is often only a few months. Regular follow-up examinations are important to monitor disease progression and adjust treatment accordingly.
Prevention
Since the exact causes of mesotheliomas in dogs are not fully understood, there are currently no specific prevention strategies. Minimizing exposure to known carcinogenic substances such as asbestos could reduce the risk, however.
Regular veterinary examinations can help detect health changes early, which increases the chances of timely diagnosis and treatment.
A healthy lifestyle, including a balanced diet and adequate exercise, can contribute to the overall health of the dog and potentially reduce the risk of various diseases, including Tumors.
Outlook on current research
Research on mesotheliomas in dogs has gained importance in recent years, as this tumor type is relatively rare and difficult to diagnose. Veterinarians and researchers are focusing on better understanding the causes and developing more effective diagnostic methods. It is believed that environmental factors, genetic predispositions, and possibly asbestos exposure could play a role, similar to humans. However, the connection in dogs is less clear, as they are less frequently in direct contact with asbestos.
Some studies have focused on identifying biomarkers that could enable early detection of mesotheliomas. These biomarkers could be detected in blood or other body fluids and help diagnose the disease at an earlier stage, which could improve treatment options. The development of imaging procedures specifically aimed at detecting mesotheliomas is also an active research area. Advances in imaging could help increase the accuracy and speed of diagnosis.
Regarding treatment, scientists are researching new drug-based and targeted therapies that target the molecular properties of mesotheliomas. Another promising direction is immunotherapy, which aims to strengthen the dog’s immune system to fight tumor cells more effectively. Clinical trials are underway to evaluate the efficacy and safety of such therapies.
An interdisciplinary approach that combines veterinary medicine, molecular biology, and oncology is considered crucial to achieving progress in combating mesotheliomas in dogs. Collaborations between universities, research institutions, and veterinary hospitals help deepen the understanding of this complex disease and develop innovative treatment approaches.
In summary, research on mesotheliomas in dogs is continuously advancing, but many questions remain open. Ongoing efforts aim to improve the quality of life and survival rates of affected dogs while gaining new insights that may also be significant for understanding the disease in humans.
Frequently Asked Questions (FAQs)
1. What is a mesothelioma in dogs?
2. What symptoms do dogs with mesotheliomas show?
3. How is a mesothelioma diagnosed in dogs?
4. What are the causes of mesotheliomas in dogs?
5. Can mesotheliomas be treated in dogs?
6. What are the survival chances for dogs with mesotheliomas?
7. Are there preventive measures to avoid mesotheliomas in dogs?
8. Are certain dog breeds more susceptible to mesotheliomas?
9. Can mesotheliomas in dogs be contagious?
10. What research is being conducted on mesotheliomas in dogs?
Literature
- Moberg, H. L., Gramer, I., Schofield, I., Guillén, A., et al. (2022). Clinical presentation, treatment and outcome of canine malignant mesothelioma: A retrospective study of 34 cases. Veterinary and Comparative Oncology, 20(1), 304–312. https://doi.org/10.1111/vco.12777
- Lajoinie, M., Chavalle, T., Floch, F., Sayag, D., Lanore, D., Ponce, F., & Chamel, G. (2022). Outcome of dogs treated with chemotherapy for mesothelioma: A retrospective clinical study on 40 cases and a literature review. Veterinary and Comparative Oncology, 20(4), 825–835. https://doi.org/10.1111/vco.12843
- Milne, E., Martinez-Pereira, Y., Muir, C., Scase, T., Shaw, D., McGregor, G., Oldroyd, L., Scurrell, E., Martin, M., Devine, C., & Hodgkiss-Geere, H. (2018). Immunohistochemical differentiation of reactive from malignant mesothelium as a diagnostic aid in canine pericardial disease. Journal of Small Animal Practice, 59(5), 261–271. https://doi.org/10.1111/jsap.12830
- Milne, E. M., Piviani, M., Hodgkiss-Geere, H. M., Piccinelli, C., Cheeseman, M., Cazzini, P., Ressel, L., Marcos, R. J., Marrinhas, C. S., Santos, M. S., Thomas, E., Drummond, D., & Martinez Pereira, Y. (2021). Comparison of effusion cell block and biopsy immunohistochemistry in mesothelial hyperplasia, mesothelioma, and carcinoma in dogs. Veterinary Clinical Pathology, 50(1). https://doi.org/10.1111/vcp.13002
- Nabeta, R., et al. (2024). Characterization of mesothelin gene expression in dogs and evaluation as a diagnostic biomarker for canine mesothelioma. Frontiers in Veterinary Science, 11, Article 1436621. https://doi.org/10.3389/fvets.2024.1436621
- Harbison, M. L., & Godleski, J. J. (1983). Malignant mesothelioma in urban dogs. Veterinary Pathology, 20(5), 531–540. https://doi.org/10.1177/030098588302000504
- D’Angelo, A. R., Di Francesco, G., De Vico, G., & Staiano, N. (2014). Sclerosing peritoneal mesothelioma in a dog: Histopathological, histochemical and immunohistochemical investigations. Veterinaria Italiana, 50(4), 301–305. https://doi.org/10.12834/VetIt.20.1309.130