Lung Cancer in Dogs
Key takeaways
Lung cancer in dogs is an uncontrolled, unnatural growth of cancer cells that affects the lungs.
- Lung cancer might be primary (originates in the lungs) or secondary (originates somewhere else in the body and spreads to the lungs)
- The cause of lung cancer is often idiopathic and not fully understood
- Exposure to some carcinogens might represent a risk factor
- This condition often presents as asymptomatic at the time of diagnosis
- Common clinical signs include cough, lethargy, vomiting, noisy breathing, and weight loss
- Diagnostics involve a complete physical evaluation, bloodwork, and diagnostic imaging
- A biopsy is usually necessary for a definitive diagnosis
- The treatment of choice is surgical removal
- Chemotherapy and radiation are also often used but are not always effective
- When treatment is not possible, supportive care helps in alleviating the symptoms
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A closer look: Lung Cancer in Dogs
Lung cancer is a relatively rare condition in dogs. It is a serious, life-threatening condition with a poor prognosis. The mean survival time for dogs affected with lung cancer is about a year and the mean age at the time of diagnosis is about ten years of age.
Risk factors
Symptoms might vary depending on the size and type of lung cancer. If a secondary infection is present, fever is a common clinical sign.
Lung cancer might also have a breed-related cause as some breeds appear to be more predisposed to it.
Abnormalities might appear if cancer spreads to other organs, such as;
- Ocular abnormalities or pain
- Lameness
- Bone pain
- Lymphadenopathy (enlarged lymph nodes)
- Palpable masses
Possible causes
The main cause behind lung cancer is still not fully understood. It is often idiopathic (the cause is not known). Exposure to carcinogens is a risk factor (a 2018 study did not find a correlation between canine lung cancer and secondhand smoke).
The most common types of lung cancer to arise are carcinomas, particularly adenocarcinoma and alveolar carcinoma.
Main symptoms
Lung cancer is often asymptomatic at the time of diagnosis, and 25% to 50% of affected dogs are diagnosed with primary lung cancer during unrelated examinations.
Testing and diagnosis
The diagnostic process consists of a full physical examination, including bloodwork and diagnostic imaging (x-ray, CT, MRI). Thoracic x-rays might show the mass, but a definitive diagnosis is usually only reached through a biopsy.
Steps to Recovery
The treatment of choice, if possible, is the surgical removal of the tumor. Sometimes, an entire lung lobe must be removed to prevent cancer from spreading.
Chemotherapy and radiation are also possible therapies but they are not always effective.
If treatment is not possible, supportive care is effective in alleviating the symptoms. Anti-inflammatories, cough suppressants, and bronchodilators might be prescribed to alleviate discomfort.
Antibiotics might also be necessary in cases of secondary bacterial pneumonia.
Referral to an oncologist is strongly suggested to determine which treatment is more suited to the specific case.
The prognosis for lung cancer varies depending on several factors. The tumor size, type, and grade, all affect the mean survival time. Other factors such as lymph node metastasis can affect the prognosis too, with normal-sized lymph nodes suggesting a better prognosis. Dogs with clinical signs also have a poorer prognosis than those that show no symptoms.
The mean survival time for dogs that undergo treatment also varies depending on tumor characteristics and the chosen treatment, but it averages around one year.
Prevention
Prevention is not always possible. Limiting or avoiding exposure to carcinogens might reduce the risk.
Lung cancer is not contagious.
Is Lung Cancer in Dogs common?
No, lung cancer is relatively rare in dogs.
Typical Treatment
- Surgical removal
- Chemotherapy
- Radiations
- Supportive care (anti-inflammatories, cough suppressants, and bronchodilators)
- Antibiotics (if secondary pneumonia)
