As in humans, lung cancer in cats can be very serious, and it can be a very scary time as a pet owner. Knowing the symptoms to look for and what to expect after a diagnosis will mean that you are well prepared if your cat is diagnosed with a lung tumor.
Quick Overview: Feline Lung Cancer
common symptoms: Dyspnea (difficulty breathing), shortness of breath (shortness of breath), drowsiness, loss of appetite, weight loss, cough, coughing up blood
diagnosis: X-ray, CT scan, MRI. Ultrasound may also be used to evaluate tumors and/or fluid accumulation in the chest.
diagnosed as a cat: rare
need to continue taking medication: Sometimes, if chemotherapy is part of treatment.
available vaccines: No
Treatment programs: Surgical resection, especially of single tumors. Applicable cases additional radiotherapy and chemotherapy. If the tumor is causing pleural effusion, a thoracentesis may be performed, using a needle and syringe to remove the fluid to help the kitten breathe better.
home remedies: not any
What is Feline Lung Cancer?
“Cancer” refers to an abnormal proliferation of cells — they grow and increase in size and number and become immune to the body’s usual “stop” signals. When these cells grow into a large mass, a “tumor” is formed.
Lung cancer (correctly called a lung tumor) is any type of tumor that grows in the lungs. This can cause a big problem because the tumor takes up the space the lungs need to work efficiently.
Types of Lung Cancer in Cats
primary lung cancer
Tumors that first grow in the lungs rather than spread to the lungs from other parts of the body are called “primary” lung tumors.
They’re fairly rare in cats, accounting for less than 1% of feline cancer cases — although these types of tumors are on the rise.
Primary lung tumors usually affect older cats (mean age 12 years) and may be more common in Persian cats.
The most common primary lung tumor in cats is lung adenocarcinoma, which can originate in the bronchi (the tubes that carry air to the lungs) or the alveoli (air sacs). Squamous cell carcinoma and bronchioloalveolar carcinoma are other types of cancer that occur in the lungs of cats.
Primary lung tumors are usually malignant and about three-quarters metastasize to other parts of the body, such as lymph nodes, bones or liver. Feline lung toe syndrome is common — this is where a lung tumor spreads to the toes, causing swelling and lameness.
While this swelling is sometimes the first symptom of lung cancer in cats, by this stage the cancer is often very advanced and unfortunately the prognosis for cats with lung finger syndrome is very poor.
secondary lung cancer
Many cancers spread to the lungs from other parts of the body, which we call “secondary” lung tumors or “metastatic lung tumors.” Almost any type of cancer can metastasize to the lungs, but lymphoma, breast cancer, and bone cancer (osteosarcoma) are the types of cancer most likely to spread to the lungs.
Because so many tumors metastasize to the lungs, secondary lung cancers are more common than primary lung cancers.
Causes of Lung Cancer in Cats
The causes of lung cancer in cats are poorly understood. We know that the number of cases is increasing, but it is not yet clear whether this is due to increased life expectancy, increased awareness, increased funding for investigations, better imaging techniques, genetics, or exposure to more carcinogens. This is likely a combination of factors.
One theory is that retroviruses such as FeLV and FIV may play a role in the risk of lung cancer in cats. Some lung cancers in other species are transmitted by retroviruses, and we know that FeLV increases the risk of lymphoma. However, there is currently no evidence that this is the case for primary lung tumors in cats.
Read more: Feline Leukemia Virus: Causes, Symptoms, and Treatment
As in humans, exposure to cigarette smoke (environmental tobacco smoke) may be a risk factor for lung tumors in cats. While there is currently no direct evidence for this, we know that passive smoke inhalation increases the risk of certain oral tumors in cats, and that passive smoking increases the risk of lung tumors in humans and dogs.
In fact, cats are in some ways more vulnerable to secondhand smoke—the toxins they ingest when grooming.
Symptoms of Feline Lung Cancer
Lung tumors in cats are often asymptomatic – Cats are masters at hiding signs of a problem and may go a long time without showing symptoms of lung cancer. In fact, it’s estimated that about one-third of lung tumors are discovered when x-rays are done for other reasons.
When cats do show signs, dyspnea (difficulty breathing) is as common as tachypnea (shortness of breath). Panting, abdominal straining while breathing, wheezing, coughing, and inability to move are also signs of a lung tumor in a cat.
Lameness caused by swelling of several toes or discharge from the nail bed due to lung finger syndrome may also be a clinical sign of lung cancer in cats.
Other symptoms of lung cancer include:
- exercise intolerance
- loss of appetite (anorexia)
- lose weight
- Nail bed secretion
- drank more than usual
- urinating more than usual
- hair loss
If your veterinarian suspects lung cancer, the first thing they will do is perform a complete physical examination, including listening to the chest. Blood tests (biochemistry and hematology) are usually done later to evaluate changes in organs that may indicate whether the cancer has spread.
This also helps to assess the safety of the anesthesia. Next comes imaging — a chest x-ray or CT scan. This helps your veterinarian determine the size of the tumor and possibly reveal metastases.
Once a tumor is found, the next step is to find evidence of metastasis. With three out of four lung tumors spreading, your veterinarian will want to know where the tumor has spread in order to give a prognosis and treatment plan.
It may be necessary to sample the tumor and examine the lymph nodes in the area, as these are common sites of metastasis. These samples are usually collected by fine needle aspiration (FNA) (also known as a “needle biopsy”), and the cancer cells are sent for cytology (analysis) by a pathologist in a specialist laboratory.
If FNA does not provide sufficient information, a larger biopsy of lung tissue can be taken under anesthesia for histopathological examination.
Feline Lung Cancer Treatment
Unfortunately, the prognosis for lung cancer in cats is poor, and treatment is often “palliative”—reducing symptoms, rather than curing the disease. Your veterinarian will discuss treatment options with a veterinary oncologist to determine the best course of treatment for your cat.
Surgical resection of the primary lung tumor or lobe is possible, especially if no metastases are detected. This involves “thoracotomy” – a major open chest surgery, usually only offered in specialist centers due to the high risks involved. If metastases are present, surgery like this is unlikely to provide enough benefit to make the high-risk procedure worthwhile.
Chemotherapy and radiation therapy (radiation therapy) are sometimes recommended, especially if metastatic spread has occurred.
If the tumor is causing pleural effusion, it may be drained to provide some relief.
Lung tumors in cats are rare, but cases are increasing, so it’s worth knowing the signs. As with all tumors, the sooner you catch it, the better, but it’s worth getting ready for bad news – the prognosis for lung tumors is often poor, especially once the disease has spread.
frequently asked questions
How long can a cat live with lung cancer?
Unfortunately, the average survival time for lung cancer is less than six months, but if the tumor is detected before it metastasizes, survival can exceed a year. The prognosis of pulmonary digital syndrome is even worse, with an average survival time of only a few months. Cats are usually euthanized for their metastatic disease.
Is Lung Cancer Painful to Cats?
Veterinarians aren’t sure if lung cancer is a pain in cats because they hide it so well. We know that 1 in 5 people with lung cancer experience pain, and lung cancer appears to cause pain in cats as well. Metastases can be painful, especially to the bone or pulmonary digital syndrome.
What Are the Symptoms of Feline Lung Cancer?
Signs of lung cancer in cats are often subtle or non-existent. When signs do exist, wheezing, lethargy, weight loss, and swollen toes are common.
Can lung cancer in cats be treated?
If caught early, lung cancer can theoretically be treated. However, most cases are not detected until late, and “treatment” is usually palliative, aimed at reducing symptoms and improving quality of life. Feline lung cancer is ultimately fatal in most cases.
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