Lung Cancer In Cats
Worried about your cat’s risk of lung cancer? While reported incidence has increased over the last 20 years, tumors originating in the lung (primary lung tumors) are rare in cats. Metastatic cancer from elsewhere in the body (spread of cancer) is more likely to cause the development of metastatic lesions in the lungs in cats.
Recognizing the signs of lung cancer can be difficult because many cats do not present with any symptoms in the beginning stages of this cancer. However, there are a few typical signs of general illness such as poor appetite, lethargy and weight loss. Some cats may experience regurgitation. Coughing can occur, though is uncommon in cats with lung cancer, especially in the early stages of this disease.
It’s possible to treat lung cancer in cats, but treatment depends on the type of cancer, tumor size and whether it has spread. After diagnosing and discussing the severity, you and your veterinarian may pursue options such as surgery, radiation therapy and chemotherapy.
Types of Feline Lung Cancer
Lung cancer describes an abnormal proliferation of cells increasing in size to form a tumor inside the lungs. Here are four types of lung cancer a cat can have:
- Bronchogenic adenocarcinoma/carcinoma: Pulmonary adenocarcinoma or bronchogenic adenocarcinoma is the most common type of primary lung tumors, arising from the bronchus. These tumors are malignant and can spread to the lymph nodes in the chest cavity, as well as to other lung lobes.
- Squamous cell carcinoma: A squamous cell carcinoma (SCC) of the lung arises from the squamous epithelium inside the lung cavity. This form of primary tumor is rare in cats but has metastatic potential.
- Histiocytic sarcoma: This type of soft tissue tumor can arise from histiocytic cells. Clinical findings and cell behavior can determine if it localized or disseminated.
- Granulomas: Small and often causing no symptoms, granulomas are benign collections of cells.
What causes cancer in cats? Unfortunately, there is no one answer as it is complex and can stem from a mix of environmental and genetic risk factors. Lung cancer can affect any breed of cat, although Persian cats are reported to have a higher diagnosis rate.
Age plays a role, as well. Most primary lung tumors are diagnosed later in life, with an average age of 12 years. Sex does not seem to affect a feline’s risk of developing lung cancer. Environmental exposure to carcinogens, such as cigarette smoke, has also been linked to lung tumor development.
Clinical Signs of Lung Cancer
The following are some of the possible symptoms of lung cancer in cats:
- Loss of appetite
- Vomiting or regurgitation
- Weight loss
- Rapid and shallow breathing
- Pain in the legs
Cats in the later stages of lung cancer may also exhibit symptoms appearing unrelated to the lungs, as the cancer may have spread. For instance, he or she may have lameness, swollen limbs or a general malaise. A syndrome specific to cats can also occur. Lung-digit syndrome is a result of the metastasis from a primary pulmonary carcinoma to the digits (toes) and can cause pain, swelling and lameness.
Diagnostics and Staging
If lung cancer is suspected, the veterinarian may perform the following diagnostic testing:
- Urinalysis and blood work: Obtain a chemical blood profile and a complete blood count (CBC)
- Abdominal ultrasound: Used to check for the presence of a primary tumor in the abdomen that could be causing a lesion in the lungs. This should help the vet determine if a cat has primary lung cancer or if a lung tumor is the result of a metastatic disease from elsewhere in the body.
- Three-view chest radiographs: Checks for the presence of a tumor
- CT scan: Establishes whether the cancer has spread to other lung lobes, the thoracic lymph nodes or the mediastinum in the chest; and helps to determine if the mass can be surgically removed
- Ultrasound-guided aspiration or biopsy: Determines the type of cancer and if the mass is malignant
Your veterinarian may recommend surgically removing the affected lung lobe where the disease is located if the lung tumor is a solitary mass. Thankfully, cats have 5 lung lobes and can do well even when one is excised. With surgery alone for a primary pulmonary bronchogenic adenocarcinoma that has not spread, the average prognosis before this tumor recurs/spreads is 1-1.5 years. If the cancer has spread to the thoracic lymph nodes or other lung lobes, surgery is not recommended.
Stereotactic radiation (SRS/SRT) is a newer and advanced form of radiation therapy to slow the progression of primary lung tumors in cats. This nonsurgical option delivers precise doses of radiation directly to the tumor, resulting in less damage to healthy tissue. There are very few side effects. If any occur, they are typically mild and may include a sunburn-like effect on the skin and inflammation in the lung tissues. SRS/SRT is a good option when the lung tumor cannot be surgically removed or if the family declines surgery but wants to pursue a definitive option. SRS/SRT will often cause these tumors to regress in size, not grow and can put the disease in a remission.
If the cancer has spread, or if the cancer has an aggressive nature, chemotherapy may be used to try to slow its progression. Chemotherapy can be used in combination with radiation therapy or surgery for aggressive disease.
Prognosis After Diagnosis
Life expectancy can depend on several factors when it comes to lung cancer in cats. Metastasis plays a big part in the time a pet may have left. For instance, if a tumor can be surgically removed successfully, a cat may live more than one year afterward. Conversely, if the disease has spread to the thoracic lymph nodes, it’s likely the cat will enter the final stage of his or her life in a couple months.
If left untreated, a tumor will continue to grow and negatively impact quality of life. Survival outlook can be discussed with your vet, and you can always seek a second opinion if feeling uncertain.
Connecting With PetCure Oncology
Has your cat been diagnosed with lung cancer? Here at PetCure, our dedicated team members understand how frightening such a diagnosis can be and are here to help in this trying time. Our mission is to provide pet owners with the best possible treatment options for their four-legged loved ones.
We encourage you to reach out to us or find a PetCure Oncology location near you.