Primary Lung Tumors in Dogs (Lung Cancer, Pulmonary Neoplasia)

Overview of Lung Cancer in Dogs

Primary lung tumors are cancers that arise in the lung tissue of both dogs and cats. They are rare in both species, but slightly more common in dogs.

The most common type of tumor is a carcinoma. Carcinomas are malignant tumors that develop from the epithelial tissues in the lungs. They may be primarily derived from the lung tissue itself, or the airways or bronchioles.

The exact cause of lung cancer is not known, but there appears to be an increased incidence of cancer in dogs that live in urban environments, as well as dogs that are exposed to second hand smoke. Lung cancer is generally diagnosed in older animals, with an average age of about 11 years, but it can also be seen in younger pets.

There are no known predispositions with respect to breed or sex and the development of lung tumors. However, most lung cancer is seen in medium to large sized dogs.

What to Watch For

Signs of lung tumors in dogs may include:

Diagnosis of Primary Lung Tumors in Dogs

Treatment of Primary Lung Tumors in Dogs

Home Care

Monitor breathing patterns and monitor for recurrence of original clinical signs. Avoid exposure to second hand smoke.

In-depth Information on Primary Lung Tumors in Dogs

The most common clinical sign seen in patients with lung tumors is a chronic cough. Usually this is a non-productive cough, which means the pet is not coughing up fluid or mucus. Occasionally pets will cough up small amounts of blood. If the tumor is large and is causing compression of the trachea or a major airway, the animal may experience dyspnea (difficulty breathing). Other causes of dyspnea associated with lung cancer include fluid accumulation around the lungs, known as pleural effusion, and widespread cancerous involvement of the lungs, leaving little normal lung tissue.

The clinical signs can also be vague and not specific to the respiratory tract. Up to 25 percent of pets with lung cancer may not show any clinical signs of illness. Occasionally dogs and cats with lung cancer are lame. This can occur because of spread of tumor to the bones of the limbs (more common in cats), or due to a secondary effect that the tumor has on bone growth (more common in dogs). The latter condition results in excess bone growth and swelling of the limbs, and is referred to as hypertrophic osteopathy. Several other conditions may cause similar clinical signs to those seen in animals with lung cancer. These include:

In-depth Information on Diagnosis

This procedure is most commonly done at specialty hospitals. If the patient has pleural effusion, this can be safely and routinely removed from the chest without ultrasound guidance. Removal of fluid may reduce the work of breathing as well as providing fluid for analysis and possible diagnosis. These methods may allow the doctor to make a diagnosis without undertaking a more invasive procedure, but it should be noted that a sample from a fine needle aspirate is never as good as a piece of tissue for biopsy evaluation.

The scope is a long tube with an attached camera, which allows visualization within the chest cavity. Depending on mass location, a biopsy may be taken using this method. However, it is unlikely that the mass could be removed using the scope. Finally, in certain cases, ultrasound guided biopsies may be performed. This is the least invasive way to obtain a biopsy, but the yield is lower with respect to sample size, and it may be a more risky procedure.

In-depth Information on Therapy

Follow-up Care for Dogs with Primary Lung Tumors

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not improve over the expected time frame.