Understanding Dog Lung Tumors: Symptoms, Diagnosis, and Treatment Options for Your Pet's Health

What Are Lung Tumors in Dogs?

Lung tumors in dogs are abnormal growths in the lung tissue. These can be primary tumors, which originate in the lungs, or metastatic tumors, which spread to the lungs from other parts of the body. While lung tumors in dogs are relatively rare, they are serious and often life-threatening. Primary lung tumors account for only about 1% of all cancers in dogs, but their impact is significant.¹

Lung tumors typically appear in older dogs, often over the age of 10.² Breeds like Boxers, Doberman Pinschers, and Bernese Mountain Dogs may be at a slightly higher risk, though any dog can be affected.³ Understanding the nature of these tumors can help guide treatment decisions and improve outcomes.

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Types of Lung Tumors in Dogs

Primary Lung Tumors

Primary lung tumors begin in the lung tissue itself. The most common type is bronchoalveolar carcinoma, which develops in the cells lining the bronchi (the large air passages that lead from the trachea–windpipe– to the lungs) and alveoli (tiny air sacs at the end of the bronchioles).

Other types include:

• Adenocarcinoma: A malignant tumor originating in glandular tissue.
• Squamous Cell Carcinoma: A rare but aggressive tumor (You can learn more about SCC in our post here).
• Carcinoid Tumors: These are uncommon and typically slow-growing.

Primary lung tumors are usually localized, making them candidates for surgical removal if caught early.

Metastatic Lung Tumors

Metastatic lung tumors originate elsewhere in the body and spread to the lungs via the bloodstream or lymphatic system. Meaning there are malignant (cancerous) cells at the source point and the lungs are a place in the body that the cancer has spread to. 

Common sources include:

• Mammary gland tumors 
• Bone tumors (osteosarcoma)
• Hemangiosarcoma

Metastatic tumors are more common than primary lung tumors. They often present as multiple various-sized nodules scattered throughout the lungs, complicating treatment.

Benign Lung Tumors

Not all lung growths are malignant. Benign tumors like pulmonary chondroma are non-cancerous but can still cause issues by compressing healthy lung tissue. While they rarely spread, they may require surgical removal if they interfere with breathing.

Inflammatory Pseudotumors

Though not true tumors, inflammatory pseudotumors can mimic cancer. These lesions result from chronic inflammation and may require a biopsy to rule out malignancy.

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Symptoms of Lung Tumors in Dogs

Recognizing the signs of lung tumors early can make a significant difference in treatment outcomes. However, symptoms often appear gradually, making them easy to overlook. As a pet parent, keeping an eye on changes your pet is exhibiting, either in their health or in their habits and personality, can help you catch a health concern early. 

Here are some common signs:

1. Coughing
   • Persistent or chronic cough
   • Coughing up blood (hemoptysis) in advanced cases

2. Difficulty Breathing (Dyspnea)
   • Labored breathing
   • Shortness of breath
   • Increased rate and effort

3. Lethargy
   • Reduced energy levels
   • Reluctance to exercise or play

4. Appetite Changes
   • Decreased appetite (anorexia)
   • Weight loss

5. Other Signs
   • Fever
   • Swollen lymph nodes
   • Pale gums (a potential sign of anemia)

Keep in mind that these symptoms can mimic other respiratory diseases, so proper diagnosis is essential. Identifying symptoms is the first step in the diagnosis process, and your vet will guide you through the rest of that journey to find the right treatment for your pet’s symptoms. 

Subtle Signs to Watch For

In some cases, symptoms may be subtle, such as a slight decrease in activity or occasional coughing. Owners might attribute these changes to aging or minor illnesses, delaying diagnosis. If you notice persistent or unexplained symptoms, consult your veterinarian promptly.

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Tests and Diagnosis of Lung Tumors

If you suspect your dog has a lung tumor, a veterinarian will conduct a thorough examination and use various diagnostic tools.

1. Physical Examination

• Checking for abnormal breathing sounds with a stethoscope.
• Evaluating the overall health and looking for signs like swollen lymph nodes or pale gums.

2. Imaging Tests

• X-rays: A common first step to detect masses or fluid in the lungs.
• CT Scans: More detailed imaging to identify tumor size, location, and potential spread.
• Ultrasound: Occasionally used to evaluate the lungs and surrounding structures.

3. Blood Tests

• Evaluating overall health, including red and white blood cell counts.
• Checking for elevated calcium levels, which can sometimes indicate cancer, but are uncommon for lung cancer.

4. Biopsy or Fine Needle Aspiration (FNA)

• Removing a small sample of lung tissue or cells for microscopic examination.
• Helps determine whether the tumor is benign or malignant.

5. Bronchoscopy

• Using a small camera inserted into the airways to visualize tumors and collect samples.

6. Advanced Molecular Testing

• In some cases, genetic testing of tumor cells can help identify specific mutations, guiding targeted therapy options.

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Treatments for Lung Tumors in Dogs

Treatment options depend on the tumor’s type, size, and whether it has spread. A multimodal approach often provides the best outcomes.

1. Surgery

• The most effective treatment for primary lung tumors if caught early.
• A procedure called a lobectomy involves removing the affected lobe of the lung.
• Dogs typically recover well if the cancer hasn’t metastasized.
• Performed most often by a veterinary surgeon.

2. Chemotherapy

• Often used for metastatic or inoperable tumors.
• Helps slow the spread and reduce tumor size.
• Common drugs include carboplatin, doxorubicin, and vinorelbine.

3. Radiation Therapy

• Targeted radiation is used to shrink tumors and alleviate symptoms.
• Often combined with other treatments for the best effect.

4. Palliative Care

• Focuses on improving quality of life when remission isn’t possible.
• Includes medications for pain management, appetite stimulation, and easing breathing difficulties.

5. Targeted Therapy

• In some cases, molecularly targeted drugs may be used to attack cancer cells without harming normal tissue.

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Prognosis

The prognosis for dogs with lung tumors varies—as with treatment methods—depending on the type of tumor, its size, and whether it has spread. 

Dogs with small, localized tumors that can be surgically removed often have a better outlook. However, the presence of metastasis or aggressive tumor types typically worsens the prognosis.

• Primary tumors: Average survival time after surgery is 12-18 months but depends on tumor type, size, grade, and stage.
• Metastatic tumors: Survival time depends on the original cancer type and response to treatment, often ranging from weeks to months.

Factors Influencing Prognosis

1. Tumor Grade: High-grade tumors are more aggressive and have a poorer outlook.
2. Overall Health: Dogs in good general health tend to respond better to treatment.
3. Early Detection: Catching the tumor early improves the likelihood of treatment leading to successful intervention.

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Prevention and Early Detection

While there’s no guaranteed way to prevent lung tumors, certain steps can help reduce risk:

1. Regular Veterinary Checkup: Annual or biannual exams can catch early signs of illness.‍
2. Healthy Diet and Exercise: Maintaining a balanced diet and regular exercise helps overall health and immune function.
3. Early Intervention: Promptly addressing any respiratory symptoms increases the chances of successful treatment.

Learn more about canine cancers and treatments on our blog.