Tumor Diseases in Cats: Everything You Need to Know

Most people are well aware that cancer can affect us humans.

Not everyone knows that it is also a relatively common cause of veterinary visits and a common cause of death in cats as well.

Many cats live a life today that is similar to that of humans. Many people eat too much and may not always eat the healthiest products. They move too little, live in cities with pollution or in the countryside with the risk of contact with chemicals used in agriculture. Both cats and humans are exposed to more and more additives, the effects of which we know very little about.

Another reason why the number of cancer diagnoses in cats is increasing is believed to be that veterinarians today have become increasingly better at treating diseases. The cats live longer and thus have time to develop tumors to a greater extent.

If you compare with dogs, the cats’ tumors are often more malignant than the dog’s.

They are often detected late in the course of the disease as cats are good at masking their disease.

In addition, there are special viruses in cats, which can increase the risk of developing tumors.

Different names

Why is the word cancer sometimes used and sometimes the word tumor?

The word cancer means cancer and derives from the growth of the cancer, that is, it spreads to surrounding tissue with arm-like protrusions. The word cancer is most often used popularly, but is not always correct.

The term cancer should actually be reserved for when it has been proven that it is a malignant (malignant) tumor that also originates from a certain type of cells.

Another type of malignant tumor is called sarcoma.

A benign tumor is called a benign tumor. Doctors and veterinarians who specialize in tumor diseases are called oncologists.


When should you suspect that the cat has a tumor? The most common is that you feel a lump somewhere. But a tumor can occur in many other ways as well; wounds that do not heal, pain in the legs (lameness), increased thirst, fever, vomiting, heavy breathing, fatigue, bleeding from any body opening or perhaps a change in behavior when defecating or urinating. These symptoms can be seen in many other diseases, but can be a sign of a tumor.

What can you do yourself?

It can be good to make it a habit to regularly feel through your entire cat. Then you can detect changes in time and then the probability increases significantly that the cat can be cured if you seek help immediately. So book an appointment if you feel a lump or something else strange. Other symptoms, some of which are mentioned above, should also cause veterinary visits if they are not just temporary ailments.


No veterinarian can say with 100% certainty what tumor it is about by just looking and feeling it. Before you can start discussing which treatment may be relevant, you must have a diagnosis, so you know exactly what type of tumor it is and if it has spread (metastasized).

Oncologists at AniCura use advanced and reliable diagnostics. We take cell samples (cytology), tissue samples (biopsy), take blood samples, X-rays, do ultrasound examinations and at some animal hospitals / clinics also have access to computed tomography (layer X-ray) and magnetic camera. We also use endoscopy (go in with a small “binoculars” in the intestine, stomach, bladder, thoracic cavity, abdominal cavity, etc.) and then also take tissue samples. In many cases, only one diagnostic method is sufficient, but in more severe cases, several methods may need to be used. Only when we have a diagnosis and know the patient’s other health conditions can we start discussing how the cat could be treated.


The treatment method that is most common, oldest and still best is surgery. In cases where the tumor is not spread and it is found at an early stage, a correctly performed surgery is often curative. One must have knowledge of the various tumors so that a proper surgery is performed from the beginning. It is always more difficult to operate a second time, if you have not removed everything at the first operation. This is why pre-surgery diagnosis is so important.

Cytotoxic therapy

For tumors that are spread or present in the blood, chemotherapy (chemotherapy) may sometimes be needed. The word cytostatics is negatively charged as it is associated with the troublesome side effects that people can get in connection with these treatments. In veterinary medicine, we also see side effects, but not as often and then less troublesome. The biggest reason is that we provide smaller doses and more gentle treatments.

They should be able to live at home and feel just as usual. If it does not work, we stop the treatment. Severe hair loss is a common side effect in humans but is very rarely seen in cats. Some may get a little poor fur quality, but most are unaffected. Some may lose their whiskers.

The goal with chemotherapy is for the patient to feel good for as long as possible. It is a difficult balancing act, we want to provide effective treatment but not cause any suffering. We therefore do not strive to cure the patient at any cost. We care about quality of life in the future instead of quantity. It is also known from human medicine that depressed patients who “give up” respond less well to treatment. We avoid this problem completely in veterinary medicine, as our patients are happily unaware of their disease. It is master and mistress who suffer the most!


In some cases, radiation is the best treatment. Radiation is used as the primary treatment for some tumors and it is also common to irradiate an area of ​​surgery when the tumor has not been completely removed. Radiation is very well tolerated by cats.

It is understandable that you as a pet owner are hesitant to start a tumor treatment. You should not make a hasty decision but first make sure to get all the information from the treating veterinarian. The word cancer scares, but it does not have to be equal to death. Many cats with tumors during treatment feel much better than animals with other chronic diseases. Be sure to be referred to a specialist if you are unsure of which treatment is appropriate for your particular animal.

Not to treat

In many cases, you may still decide not to treat, but it is easier to make a decision after receiving all the information about the prognosis and treatment options. You should also never forget that you do not have to complete a treatment just because you have started it. If you as a pet owner feel that it does not feel good or that the cat does not seem to feel well, you can end the treatment.

Sometimes there is nothing you can do, but the best thing for the cat is to let it fall asleep for good. In those cases, you should not wait too long. The grief becomes heavy, no matter when we make the decision. Cats live in the present, and can not, like us, think back on life, remember wonderful moments or plan for survivors.

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