Our beloved feline friend can also fall victim to cancer, a disease that, if not detected and treated in time, can be fatal. Although there are several types of cancer, and all are cause for concern, respiratory carcinoma is one of the most significant and frequent tumors in cats , as it directly affects the lungs and their ability to breathe normally.
Cats are experts at hiding pain and discomfort , so it's up to us to be very attentive to any changes in their behavior or daily routine. A seemingly insignificant detail, such as a slight cough or a gradual loss of appetite, can indicate that their health is declining. To help you, we'll explain in detail what respiratory carcinoma in cats is, its symptoms, how it's diagnosed and treated , as well as possible complications and the prognosis.
What is respiratory carcinoma?
Respiratory carcinoma, commonly known as lung cancer or cancer of the respiratory tract , is a disease in which abnormal, malignant cells form in the tissues of the airways. It can affect the lungs , nasal passages , and even the sinuses , compromising proper airflow and oxygen exchange.
In the lungs, these cells grow uncontrollably, forming tumors that can obstruct the bronchi, invade healthy lung tissue, and spread to other parts of the body through the blood or lymph, a process known as metastasis . When the tumor originates directly in the lung, it is called a primary lung tumor ; if it comes from another organ, it is called a metastatic or secondary lung tumor.
It can originate in different types of cells, so there are several main types of respiratory carcinoma in cats:
- Squamous cell carcinomaAlso called squamous cell carcinoma, it originates in the thin, flat cells that line the airways or nasal mucosa. It is aggressive and has a high capacity to invade nearby tissues.
- Undifferentiated large cell carcinomaIt develops in the more peripheral areas of the lungs, on the outer edges, and usually has a very malignant behavior.
- adenocarcinomaIt originates in the glandular cells of the lungs and under the lining of the bronchi. It is the most frequent type of primary lung tumor in cats and can spread to bones and other organs.
In addition, metastatic lung tumors can occur, originating from other feline cancers (such as mammary, bone, or skin tumors). In many cats, these metastases represent a significant proportion of the tumors seen in the lung.
Causes and risk factors of respiratory carcinoma in cats
The exact causes of respiratory carcinoma in cats are not fully understood, but factors that increase the risk have been identified :
- Advanced ageMost cats with lung tumors are older, when the body has accumulated more cellular damage and the immune system is less efficient.
- Genetic predispositionAny cat can develop cancer, but certain certain breeds seem to be somewhat more predisposed, such as conjoined twins or Persians, and also those with a family history of tumors.
- Exposure to environmental toxins: The smoke of the tabacco (including electronic cigarettes), harsh cleaning chemicals or household air pollutants can chronically irritate the respiratory system and promote the appearance of malignant cells.
- Chronic diseasesLong-term respiratory conditions or systemic problems (cardiac, renal, endocrine) can weaken the immune system and decrease the body's ability to control the appearance of tumor cells.
- decreased defensesA weakened immune system, whether due to age, sustained stress, or illness, makes it more likely that abnormal cells will escape the body's normal control and form a tumor.
These factors are not always identified in a cat's history, but reducing exposure to smoke and chemicals , providing a quality diet, and conducting regular check-ups with the veterinarian helps to care for their respiratory system and overall health.
What are the symptoms?
Respiratory carcinoma in cats can be deceptive: in its early stages, it may be subtle or even asymptomatic . In fact, in many cats, lung tumors are discovered incidentally when X-rays are taken for other reasons. Even so, there are signs that should raise a red flag.
As the disease progresses, the cat may suffer primarily from a persistent cough and difficulty breathing . You might notice that it's breathing faster even at rest, panting for no apparent reason, or becoming fatigued with minimal exertion, such as climbing stairs or playing for a short time.
Other general signs should also not be ruled out, such as loss of appetite , progressive weight loss , apathy , sadness, general malaise , and depression. Often, these behavioral changes appear before the obvious respiratory symptoms.
Adenocarcinoma and other lung carcinomas can spread to the bones of the legs and toes , causing lameness, severe pain, and bone destruction, a condition known as feline digitopulmonary syndrome . In these cases, lameness or lesions on the toes may be the first sign of an underlying lung tumor.
Other signs that may appear in cats with respiratory carcinoma include:
- Accelerated breathing (tachypnea) or breathing with visible effort in the abdomen.
- Wheezing or abnormal breathing sounds, similar to whistling.
- Sneezing or runny noseespecially if there is involvement of the nasal passages or paranasal sinuses.
- Slight fever if there is a secondary infection or severe inflammation of the lung tissue.
- Pleural effusionThat is, an accumulation of fluid around the lungs, which causes marked dyspnea and strange postures to try to breathe better.
If our cat shows any of these signs, even if they seem mild or isolated, we must take it to the vet as soon as possible . The animal's life and future quality of life may depend on an early diagnosis.
Diagnosis of respiratory carcinoma in cats
To confirm the presence of respiratory carcinoma, a complete diagnostic process is necessary . The veterinarian will begin with a physical examination and a detailed history, asking about the duration of symptoms, weight changes, appetite, and activity level.
Chest X-rays are one of the first imaging tests used. They allow doctors to see lung masses, changes in the pattern of lung tissue, and, in many cases, detect single tumors or multiple lesions spread across several lobes. They can also show signs of pleural effusion.
In cases where greater precision is needed, computed tomography (CT) is used , which provides detailed images of the inside of the chest. This technique is very useful for assessing the exact extent of the tumor , whether it invades nearby structures, and whether there are lung metastases or metastases in other thoracic tissues.
Lung ultrasound has also become a very useful tool for identifying areas of pulmonary consolidation, nodules and pleural fluid , as well as allowing guidance of fine needle puncture to obtain tissue or cell samples.
To confirm a respiratory carcinoma and determine the exact tumor type, a sample must be analyzed using cytology or biopsy . This can be obtained via ultrasound-guided fine-needle aspiration, thoracoscopy, or surgery. Histopathological examination reveals whether it is an adenocarcinoma, squamous cell carcinoma, or another type, and assesses its aggressiveness.
Along with these tests, comprehensive blood work is usually performed to assess the cat's overall health, as well as abdominal ultrasound or other imaging techniques to look for metastases in other organs. All of this allows the stage of the disease to be determined and the most appropriate treatment to be chosen.
Which is the treatment?
The treatment for respiratory carcinoma in cats will depend on the nature of the tumor, its size, location, the cat's age, and the presence of metastasis . Whenever possible and the tumor is well-defined, the preferred option is surgical removal of the mass , usually by resection of the affected lung lobe (pulmonary lobectomy).
In single primary tumors, without evidence of spread to other organs, surgery can offer a significant improvement in quality and length of life . However, it is a complex procedure requiring general anesthesia and a period of hospitalization and postoperative pain management.
When the disease is more advanced, the tumor is multifocal, or metastases are present, surgery may not be an option. In these cases, the veterinarian may recommend chemotherapy and/or radiation therapy to try to stop or slow tumor growth. Chemotherapy uses antineoplastic drugs that target cancer cells, while radiation therapy uses high-energy radiation directed at the tumor masses.
In some cats, metronomic chemotherapy protocols are used , with low and continuous doses of certain drugs, the aim of which is to reduce the formation of new blood vessels that feed the tumor and control its progression with fewer side effects.
In addition, a supportive care approach is essential : adequate analgesia for pain control, oxygen therapy if the cat has respiratory difficulty, bronchodilators in case of cough or bronchoconstriction, treatment of pleural effusion if present, and nutritional support to prevent excessive weight and muscle mass loss.
Cancer is not a disease to be taken lightly. We must keep in mind that the sooner the diagnosis is made and treatment begins, the more years we can have our cat with us , and the better the chances of maintaining their quality of life.
Prognosis and prevention
The prognosis for respiratory carcinoma in cats is guarded and varies considerably depending on the type of tumor, how quickly it is detected, the feasibility of surgery, and the presence or absence of metastasis. Cats in whom complete resection of a single tumor without spread can be performed generally have a longer life expectancy than those with advanced disease and pleural effusion.
While it's not always possible to prevent this cancer, we can reduce some risk factors . Avoiding tobacco smoke at home, limiting exposure to irritating chemicals, eating a balanced diet, and maintaining a healthy weight are all measures that support the immune system and respiratory health.
Regular veterinary checkups , especially for older cats, are key to detecting any abnormalities early. Seeking veterinary care for persistent coughing, changes in breathing, weight loss, or unexplained lameness can allow tumors to be discovered at more treatable stages.
Caring for a cat with respiratory carcinoma involves combining the best possible veterinary care with a calm environment, affection, and daily monitoring of its condition. Detecting small changes and acting quickly can make a big difference to its well-being and the amount of time we can continue to enjoy its company.