Cancer in Cats | Types, Treatment and Prevention

Picture of sleeping cat

Although it is less common in cats than it is in dogs, cancer affects many of our feline companions. Because cats are extremely good when it comes to hiding illnesses, the symptoms could often go unnoticed by their pet parents. Unfortunately, what that means is that the cancer is diagnosed later, which makes its treatment a lot more difficult and a lot more costly, too.

Cancer is a general denomination because there are many types of neoplasia that can affect cats. Some develop in certain tissues, some are localized and won’t spread out to other organs, while others can evolve more rapidly compared to others. All of these factors have to be assessed by the medical professional when your cat is diagnosed with a specific type of cancer.

Let’s look at some things you have to know about preventing and treating cancer.

Common Cancers Found in Cats

Lymphoma is one of the most common types of cancers that cats are affected by. Usually, it is associated with FeLV (Feline leukemia virus), and although there is a vaccine for this disease now, many cats are exposed to it before receiving the shot.

Mammary tumors are also common in cats that are not spayed. Fortunately, because many pet parents spay their feline companions nowadays, the likelihood of their cats developing this type of cancer has decreased over the years.

Squamous carcinoma is another type of tumor that affects the connective tissue of the body, and that can show up in the spots where the cat has received vaccinations or injections. That’s why some vets call this type of cancer injection-site sarcoma.


Externally, you can notice bumps or lumps when you pet your cat. However, these are only noticeable if your cat has a form of mammary cancer, for example, but needless to say, you can’t see inside your pet’s body to tell what’s wrong.

Diarrhea and vomiting are two signs that a gastrointestinal lymphoma might have developed, and for cancers that cause fluid in the lungs, difficulty in breathing is a symptom you might be able to notice.

Lethargy and weight loss should also give you a clue that you need to take your cat in for a quick check-up, but these can be caused by a variety of medical conditions — not just cancer.


Staging the cancer is necessary before any kind of treatment is initiated. What this means is that, while diagnosing the condition, the veterinarian will want to find out whether there are any complications and exactly how far the tumor has spread. Staging a neoplasm can happen via X-rays or ultrasonography, but getting samples from the tumor via biopsy or aspirate is more precise.

Once the stage is set, the treatment begins depending on the type of tumor. In general, there are three kinds of cancer treatment and they consist of surgery, radiation therapy, and chemotherapy. However, the right one is only decided upon after the vet has determined the type and location of the neoplasm, whether there are any metastases, whether the treatment is appropriate for the age and health state of your cat, and if it is feasible or available to you.


Surgery is one of the most successful types of treatment, but it is only performed when the removal of the tumor is actually possible. Besides, if the animal has metastases in one or several other organs, sometimes it makes little to no sense to perform surgery, especially if the cat is suffering from a form of invasive cancer. Non-invasive cancer is usually treated using this method.

Surgical treatment calls for the removal of the tumor, but also the tissue around it. Why is that? Many tumors spread microscopically, and while it might be impossible to see any modifications with the naked eye, the cancer could have affected the neighboring tissue within the same organ or this tissue could contain a number of abnormal cells that could lead to a recurrence following the treatment.


There are many misconceptions regarding chemotherapy, and that’s because many people think that it has multiple side effects that might lead to the cat becoming more sick than he or she is now with the cancer still growing inside the body. The truth is that cats tolerate anti-cancer drugs a lot better compared to many other species, and oftentimes, they are prescribed low doses so that the specialist can assess the presence and severity of the adverse reactions.

The type of chemotherapy that the vet will choose for the cancer patient depends on how the tumors can be treated, the medication available for the disease, as well as whether the patient tolerates this type of treatment or not. To increase the effectiveness, as well as to combat some of the side effects, the cat might have to take several types of drugs.

Some of the common side effects that cats undergoing chemotherapy might experience are hair loss, gastrointestinal irritation, and suppression of the bone marrow, which causes a low white blood cell count and as a result, your pet’s immune system becomes weaker. Usually, less than twenty percent of the patients will be affected by any adverse reactions.

Radiation Therapy

Unfortunately, this is one of the least available forms of treatment, especially for cats. Compared to chemotherapy, it has significantly fewer side effects, and it actually does kill many types of tumors. The only adverse reactions that you’ll notice and that your cat will experience are hair loss and skin irritation at the site where the radiation therapy was performed.

Caring for a Cat That Has Cancer

Whether one of these types of treatment was initiated or not, there are some things you have to know about, and that can considerably improve the quality of life of your feline companion. It is a good idea to keep tabs on the nutritional intake because it is important that the animal receives plenty of nutrients that help the pet put up with the effects of the treatment.

Supportive therapy can be made available, as well, and it can range from using anti-emetic drugs or analgesic medication to administering antibiotics if a bacterial infection has also become a problem when the white cell count has decreased due to chemotherapy.

Can Cancer Be Prevented?

What makes preventing cancer so challenging is that its causes remain unclear. Some types of cancers are transmitted genetically, and if you adopt a stray cat, there’s no way of you knowing whether your pet’s parents were affected by a type of cancer or not. Feline leukemia virus is contagious, so at least there’s that as a cause. Talk to your vet about vaccines.

Given that there is a wide range of chemicals that can predispose your feline companion to develop cancer, the only type of prevention you can ensure is to keep everything in your cat’s environment as natural as possible. This means that you should use household cleaning products that contain no toxins but also prevent exposure using other means. Even using bug spray can increase the risk.

When it comes to nutrition, many commercial grade foods for cats contain a lot of preservatives and artificial colors, which means that while they might provide the necessary fuel that your cat needs throughout the day, they aren’t exactly healthy. As a general rule, stick to premium brands that use quality ingredients and that create diets that have a short shelf life.

As for the variety of colors in your cat’s kibble, they are worthless. They are only visually appealing to you. Cats rarely (if ever) consume food based on how it looks. Their sense of smell determines whether they are interested in trying it out or not, and once they take a bite, they might also be convinced by the food’s consistency. This is the reason so many cats like ice cream and will even drink cow milk even though they weren’t genetically designed to have a preference for these foods. But given their fat content, they will want to eat them.

If you are ever in the market for a new type of cat food brand, our advice to you is to pick one that has no artificial colors, additives, flavors, and preservatives.

Finally, one of the best ways of preventing cancer or at least discovering it before it’s too late is to take your cat to the vet every year for a blood test and a general examination.



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