The Most Common Types of Cancer in Cats

4 minutes

Tumors or leukemia affect one in five cats, and have serious consequences for the animal.

Written and verified by the lawyer Francisco María García.

Last update: 21 December, 2022

This set of cells that grow abnormally and divide uncontrollably are a threat to all living beings. Therefore, knowing which types of cancers are most common in cats can help prevent them from spreading.

Cancer is the main cause of death in cats. One in every five cats have cancer, so it is important to detect it at an early stage. These masses or tumors form when cells start to multiply at a very fast rate. They end up becoming malignant or benign depending on that speed and the cells’ ability to invade other tissues. In general, cancer is divided into sarcomas or carcinomas.On the other hand, leukemia is a cancer that affects the bone marrow, which is where blood cells are made. This causes an outflow of a large number of abnormal cells into the bloodstream and the irregular growth of lymphocytes, which is a blood cell that causes lymphoma.

How Does Cancer Appear?

Genetic predisposition, exposure to sun rays or carcinogenic chemical agents can trigger different types of cancer in cats. Infections such as feline leukemia virus or feline immunodeficiency virus, favor some types of cancer to develop in cats. Fortunately, both are easy to detect.

Prevention, is not always simple. Feeling weak, weight loss, loss of appetite, lumps on or under the skin, bleeding, changes in the eyes, or wounds that don’t heal, require an immediate medical attention from the veterinarian. A strange meow, fur that’s in bad conditions, or a lack of rest are also indicators that something is wrong with a cat.

X-rays, ultrasounds, surgical or biopsies, and needle aspirates help detect different types of cancer in cats. It’s important for cat owners to periodically run routine blood tests on the animal, especially in older cats.

Computerized Axial Tomography (CAT) and Magnetic Resonance Imaging (MRI) are sophisticated techniques that confirm the diagnosis and allow for tailored treatment plans.

Most Common Types of Cancer in Cats

Lymphoma or lymphosarcoma is the most common cancer in cats, and the solid tumor originates in the white blood cell called lymphocyte, which is related to the immune system. It can appear in several places at once such as the lymph nodes, thoracic cavity, gastrointestinal tract, nasal cavity, kidneys and nervous system.

Surgery, chemotherapy and radiotherapy are other possible treatment options. A cat can get a positive outcome with one or more of these treatments. It’s not always easy to treat a cat with cancer, but providing the cat with an excellent quality of life needs to be the priority.

On the other hand, squamous cell carcinoma — that are triggered by sun-rays — affects the skin. These tumors usually affect the nose or ears, and it may look like a scratch or wound that doesn’t heal properly. However, metastasis is not as common.

Mammary carcinoma affects the mammary glands. It mostly attacks non-spayed females, although non-spayed cats are not safe from it either. Interestingly enough, neither are males. Multiple nodules or swollen and hardened areas are red flags because they can spread to the local lymph nodes and lungs.

Finally, early treatment of single and small nodules makes a difference. Extirpating the tumor and its adjacent tissues, and sometimes chemotherapy, are god tools to fight cancer.

Variations of Cancer in Cats

Mastocytoma affects the skin, spleen or intestines, where it is usually very aggressive, because it causes obstruction. It metastasizes easily, especially in the lymph nodes, lungs, liver or spleen. Surgery, radiotherapy or chemotherapy are curative options for this case.
Oral squamous cell carcinoma originates in cells lining the mouth or throat. It affects the tongue, and sometimes invades local bone and lymph nodes. It usually causes difficulty eating, salivation and halitosis. This type of cancer is difficult to treat.
Fibrosarcoma or soft tissue sarcoma forms in connective tissues under the skin. Experts recommend treating this type of cancer by combining surgery with radiotherapy and chemotherapy. However, the prognosis may vary.
Osteosarcoma affects the bones in the extremities, spine or skull. It produces fractures, a lot of pain and lameness, and can spread to the lymph nodes and lungs. Again, surgery, radiotherapy and chemotherapy can be a solution.

Types of Lung Cancer in Cats

Respiratory, nasal or pulmonary carcinoma are the most frequent in the nose and lungs. They cause difficulty breathing, snoring or snorting, sneezing, coughing and nasal discharge. It can spread to the bones, and usually it has already metastasized when clinical symptoms appear. Surgery and chemotherapy are effective alternatives.
Adenocarcinomas affect both the large and small intestines, and are extremely invasive. They grow very quickly, cause loss of appetite, weight loss, vomiting and diarrhea. Additionally, it usually extends to local lymph nodes. The indicated treatment is surgery.
Pancreatic and hepatic adenocarcinomas of bile ducts aren’t very common. They cause jaundice, depression, weight loss, vomiting and abdominal distension. Unfortunately, prognosis usually has a negative outcome.