Lung cancer in dogs is almost always secondary in nature. Cancerous cells spread from other parts of the body to affect the lungs. Primary lung cancer or cancer that originates from the cells of the lungs, airways or bronchioles is rare in cats and dogs, but is relatively more common in dogs as compared to cats.
The most common type of primary lung cancer is carcinoma, a malignant tumor derived from the epithelial tissue. It is one of the four major types of cancers. Dogs that are exposed to secondary smoke are at a higher risk, as they live in urban areas. Like most other canine cancers, lung cancer is seen more in older dogs and does not present significant symptoms in its early stages.
A non-productive chronic cough (dry cough without throwing up mucus or fluid) is one of the major symptoms that indicate problems with the lungs and the upper respiratory tract. A cough that produces blood is a sign that indicates that lung cancer has progressed. Other signs of progression include labored respiration (a condition known as dyspnea). This occurs when the tumor is large enough to pressurize the trachea. However, dyspnea can also be caused by swelling from excessive accumulation of watery fluid around the lungs (edema or pleural effusion). Some dogs may show signs of lameness as lung tumors tend to metastasize to limbs, and also have a secondary effect on bone growth.
Most lung tumors are in the shape of a single abnormal mass, and a preliminary diagnosis is usually done with X-Rays of the chest. Chest X-Rays also help to rule out edema and reveal the size of the heart and cardiovascular network. If a tumor is seen, examination with a fine needle aspirate and biopsy of lung tissue may have to be done to confirm malignancy.
Cancer treatment in dogs follows the same path, irrespective of the type of cancer and where it occurs. The available choices remain the same - surgery, chemotherapy and radiation therapy. Homeopathic cancer treatment of dogs can also be considered to halt progression of the disease.
In the case of primary lung cancer, surgery is the preferred treatment if the tumor is small, because complete excision may not be possible in all cases. Surgery is ruled out in cases of metastatic lung cancer. Chemotherapy, after surgery or as a primary treatment choice, has shown good results in controlling the progression of lung cancer. Lung cancer usually proves to be fatal, and after treatment, you will be required to provide extra home care to monitor the side effects of strong drugs and provide comfort for as long as the dog lives.