Cancer in any part of the body can be primary or secondary. The specific cancer is called primary cancer if the cancerous growth is known to have originated from the tissue of the organ itself. The cancer is called a secondary cancer if it has metastasized (spread) to the organ from another organ or tissue. For example, when diagnosed, if lung cancer is known to have developed in the lung tissues, it is called primary lung cancer. On the other hand, if the lung cancer that is diagnosed has spread from another part of the body (e.g., the liver), it is called secondary lung cancer.
Primary lung tumors may occur in the lung tissue or the bronchioles, the smallest bronchial ducts. The most common type of lung tumor is carcinoma, which is a malignant tumor derived from epithelial tissue.
There is no known cause of feline lung cancer as of yet. However, it is seen mostly in cats that live in urban environments that are therefore exposed to secondary smoke. In the initial stages, symptoms similar to feline upper respiratory infection like chronic coughing (non-productive) can be observed. As the disease progresses, some of the symptoms to watch out for include:
- Loss of weight.
- Coughing up blood.
- Appetite loss.
- Dyspnea (difficult or labored respiration).
Further progression of the disease may lead to pleural effusion or accumulation of fluid around the lungs. Eventually, cancerous cells affect the entire organ, with minimal proportions of normal lung tissue. However, in at least 25% of the cases of lung cancer, the clinical signs relating to feline respiratory disease remain concealed for a long time. In many cases, it is too late to treat the disease.
A complete history and physical examination is necessary to establish the prevalence of a lung tumor. A veterinarian is able to decipher between normal and abnormal sounds by listening to the sounds within the cat’s body. Muffled sounds from the lungs usually indicate dyspnea, and careful listening reveals whether it is due to a heart disease or not.
Complete laboratory tests, blood and urine analysis are done to evaluate red and white cells, platelets, blood sugar and blood proteins. Certain tests for the liver and kidney are also carried out. The final diagnosis is prepared only after chest radiographs, abdominal ultrasound examination, analysis of aspirate of lung mass and biopsy.
If pleural effusion has occurred, the fluid is removed from the lungs when required to ease feline respiratory problems, including dyspnea. The fluid is sent for examination, which may indicate the prevalence of a tumor and may amount to bypassing invasive diagnostic procedures. However, an aspirate is not as reliable for a confirmed diagnosis as a piece of lung tissue.
Chemotherapy is not very effective in most cases of lung cancer. It may be advised only as post-surgical treatment. In cases of single lung tumors, the involved lobe is removed along with the mass, but surgery is ruled out if cancer has spread and distributed to a great extent. Follow-up home care and veterinary care is critical after surgery, especially if your cat does not show signs of improvement within a set time frame.Sources