Top 10 Cancers in Cats

Picture of a long haired grey cat

Cancer has started to affect pets a lot more these days, especially since they live much longer compared to what they used to even 50 years ago. Better veterinary care and the fact that some cats are kept indoors for most of their lives ensure a longer life span.

Unfortunately, older cats are also more predisposed to developing cancer, as is the case in humans. In today’s article, we are looking at some of the most common types of neoplasms that cats can get.

Before we move on, we’d like to note that the causes of feline cancer remain unclear even now, but that in most cases, neoplasms are a result of genetic factors, environmental factors (such as exposure to toxic and carcinogenic substances), and viruses.


This type of cancer is much more common in cats that spend some of their time outdoors, too, as they can get infected with FeLV. It used to be the most common type of neoplasm affecting this species, but in the recent several years, pet owners have massively begun to vaccinate their pets against it, so it is now preventable.

Outdoor cats have to get a shot against this type of cancer every year.

As for the disease, it affects all lymphocytes and lymphoid tissue in the cat’s body, so it can affect any organ from the spleen and liver to the gastrointestinal tract and, of course, the animal’s lymph nodes.

Squamous Cell Carcinoma

This is another particularly common cancer of cats, and it tends to affect their oral cavity and skin. Unfortunately, some animals go undiagnosed for a long amount of time, which means that therapy becomes complicated.

Some forms can be extremely aggressive, and so the veterinarian’s prognosis is poor. If your cat has a bump on her nose, has trouble eating, and she’s drooling a lot, it might be a good idea to go to the vet.

Note: in this case, your cat could be suffering from calicivirus, not an oral tumor, but going to the vet can lead to a clear and accurate diagnosis and the appropriate treatment.

Mammary Tumors

Did you know that approximately 90% of tumors of the mammary gland in cats are malignant? This means that they can spread to any of the organs present nearby, and usually these metastases are location-based.

In other words, if your cat develops a tumor of one of her lower mammary glands, it could metastasize to one of her abdominal organs (including the peritoneum, the abdominal lining).

On the other hand, if your cat develops a mammary tumor on her chest, the tumor could spread to her lungs. For this reason, veterinary assistance is necessary whenever you notice a lump on your cat’s belly or chest.

Chest Cancer

Described generically as chest cancer, this is any type of tumor that affects the cat’s lungs, lung lining, or thoracic muscles/skin. Whether it is a metastasis of mammary neoplasia or a primary tumor, the worst thing about this type of cancer is that it often goes unnoticed and undiagnosed.

Cats that have thoracic cancer can show a variety of clinical signs, from shortness of breath and a persistent shallow cough to lethargy, vomiting, or withdrawal.

Intestinal Cancer

While intestinal cancer isn’t as common as some of the other types we have already mentioned, the section of the feline gastrointestinal tract that seems to be the most affected one is the small intestine. Of course, cats can also develop cancer of the stomach and large intestine, but they’re usually less common.

There’s also a predisposition in terms of gender as it tends to affect males more than it does females.

Hepatic Cancer

Although it’s typically one of the most aggressive types of cancer that all pets can develop, liver neoplasia often goes unnoticed until the development of the disease has made therapy very difficult.

Hepatic cancer can also be a primary tumor (usually primary adenocarcinoma) or it can show up as a result of metastasis from mammary gland tumors. It is more common in geriatric animals, so if your cat is older than 8, take her to the clinic for a checkup at least once every six months.

Bone Cancer (Osteosarcoma)

A cat’s skull and jaw are the two places where this type of tumor can more commonly develop in cats, but it can sometimes also affect the animal’s limbs. If that’s the case, the cat will be reluctant to move, be lethargic, and show a decrease in appetite.

Unfortunately, osteosarcoma is among the most painful types of feline cancer.


This type of cancer tends to affect the cat’s skin, but it can sometimes be caused by vaccinations.

Unfortunately, vaccines are essential for keeping an animal healthy, and as necessary as they might be, they are associated with a number of risks, including this locally aggressive tumor. Scientists are working on making shots better for cats so that this risk is lowered as much as possible.

Abdominal Lining Cancer (Cancer of the Peritoneum)

Peritoneal cancer doesn’t affect cats as much as it does other animal species, including dogs, but since the peritoneum is the first tissue that cancerous cells coming from other primary tumors encounter (such as fibrosarcomas or mammary tumors), it can be detected.

However, primary tumors of serosal surfaces in animals are quite uncommon, so almost always, a peritoneal tumor is a metastasis. Since this type of cancer is usually diagnosed in its late stages, it has a poor prognosis.

Nasal Cancer

Cancer of the nose or the sinus cavity is less common compared to the others we’ve described, but we’re mentioning it here due to its aggressiveness. It can quickly spread to other tissues in the area, including the brain, which can lead to significant health complications.

Some clinical signs to be on the lookout for range from a deformed nose to excessive tearing or sneezing.

Final thoughts

As you might have noticed, cats can develop cancer just like any other species, but the key to extending your pet’s life and making sure that she gets treatment at the right time is to go to regular veterinary checkups.

Sometimes, even blood tests can reveal some issues that your vet might want to investigate further, and following the diagnosis, manage to save your cat’s life.



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