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Finding out that your cat has cancer is a worrying time, but sadly it’s not an uncommon diagnosis. In many cases, early diagnosis can result in more chance of the cancer being treatable, so it’s important to take your cat to the vet as soon as you notice something is wrong.

What is cancer in cats?

Cancer in our cats can take many forms, from lumps and bumps you can see to things internally.

There are different forms of cancer and lumps, including:

  • cancer – a type of cell starts to divide in an uncontrolled way, this can create a growth or lump, or can be more widespread where the abnormal cells spread in an area such as the intestines, or the blood or bone marrow. Cancer can also be called neoplasia and is generally used to describe malignant disease
  • tumours – a solid collection of abnormal cells, which either grow and divide too quickly, or don’t die when they should. May also be called a growth, mass or lump
  • benign tumours – do not spread to surrounding tissues or other parts of the body
  • malignant tumours – abnormal cells spread to surrounding tissues or ‘metastasise’ to other parts of the body

Find out more about lumps and bumps on cats

Types of cancer in cats

There are different types of cancer affecting different body systems in cats, just like in humans. Some of the most common include:

  • lymphoma (also called lymphosarcoma) – the most common type of cancer in cats, this affects a type of white blood cell (the lymphocyte). This cell is normally involved in the immune system (the part of the body that fights off disease) and is found in many areas of the body. Therefore, lymphoma can also be found in different parts of the body and cause a range of symptoms. Most frequently the intestines are affected
  • squamous cell carcinoma – a common cause of mouth tumours, this cancer can also affect the skin, especially on the ears and nose secondary to sun exposure, and occasionally other places
  • basal cell tumours – these are the most common skin tumour in cats. They are benign, so an operation to remove them is normally curative
  • sarcomas or fibrosarcoma – arise from the cells which create supportive tissue in the skin, muscle and bone, these most commonly start as a firm lump growing under the skin. These tumours vary in how malignant they are, both in terms of the degree of spread and time taken for this to occur
  • carcinomas/adenocarcinomas – the second most common intestinal tumour, these are malignant tumours that can also be found in other areas of the body, such as the lungs or mammary glands
  • mast cell tumours – these can be benign or malignant. They are the most common tumour of the spleen in cats (although overall this is a rare type of cancer), they are the second most common skin tumour, and third most common intestinal tumour in cats

Signs of cancer in cats

Your cat’s symptoms will vary depending on the type of cancer they have, but some more common signs and symptoms of cancer in cats can include:

  • weight loss
  • vomiting and diarrhoea
  • problems eating and chewing
  • being more tired
  • sores that don’t heal
  • lumps and bumps

A lot of the potential symptoms of cancer in cats could easily be caused by other conditions, so it’s important to get them checked out with the vet as soon as you notice something is wrong.

Remember not all lumps and bumps are tumours. Find out more about lumps and bumps on your cat on our free advice page.

How do cats get cancer?

We don’t always know what causes cancer to develop in cats, however certain cats are more at risk of getting cancer. These include:

How is cancer in cats diagnosed?

Your vet will usually need to do some tests to determine whether your cat has cancer and what type they have. Tests will depend on where the cancer is suspected, and what type of cancer it is likely to be.

These can include:

  • blood tests – can be used to assess the overall health of your cat, look for organs affected by cancer or other disease processes which could be causing the symptoms, and test for the viruses feline leukaemia virus and feline immunodeficiency virus
  • imaging – can include x-rays, ultrasound, endoscopy (using a camera) and CT or MRI. This helps to assess the changes which can be associated with cancer, and to look for spread
  • taking samples – your vet may collect cells from the tumour via a needle, which is called a fine needle aspirate, or a larger section of the tumour may be removed surgically, which is called a biopsy. The cells and body tissue will be looked at under the microscope. Sometimes extra testing can be performed to give more information on the cells to see if they are cancerous

Can my cat’s cancer be treated? How is cancer in cats treated?

Options for cancer treatment will depend on the type of cancer your cat has, how aggressive it is and what stage their cancer is at. Different cancers will require different treatments and ongoing care, so ask your vet for guidance and advice.

Some common cancer treatments can include:

  • chemotherapy – your vet will let you know if they think your cat is suitable for chemotherapy. This treatment involves giving your cat special medication which is designed to stop the cancer cells growing and spreading. If your cat undergoes chemotherapy, you will need to take extra precautions cleaning up after them (for example, wearing gloves when cleaning their litter tray and putting waste in a sealable bag) and talk to your vet about any potential side effects
  • radiotherapy – your vet may refer your cat to a specialist if they think radiotherapy would be suitable for your pet. Radiotherapy is targeted at tumours to kill off the cancerous cells. As with chemotherapy, there can be side effects which you should discuss with your vet or specialist
  • surgery – depending on the location of your cat’s tumour, your vet may be able to remove it with surgery

Will I need to put my cat to sleep if they have cancer?

Saying goodbye to your cat is a very difficult decision to have to make. Not all cancer will mean needing to say goodbye to your cat. Some cats will have a cure or long-lasting treatment, allowing them to express all their natural behaviours free from pain or suffering.

Other cancers may not respond to therapy, or be very aggressive to the point that at diagnosis a cat is already suffering, with little option to ease this. Some cancer treatment can be costly or invasive, and won’t be right for every cat or carer. Quality of life is an important consideration in all decisions in cats with cancer, and sometimes the kindest decision will be euthanasia.

Putting your cat to sleep is a very hard decision. If you are upset and need someone to talk to, our free Paws to Listen grief support service can provide you with a sympathetic ear at this difficult time. Find out more about our Paws to Listen service.

You can find out more about when to say goodbye on our advice page.

How can I stop my cat getting cancer?

Sadly, most cancers are not preventable and the best thing you can do is keep an eye on their health, take them for regular check-ups and contact your vet if you notice anything wrong with them.

The chance of some cancers developing can be reduced by protecting your cat against feline leukaemia virus by vaccination, neutering female cats from four months of age, and using sun protection, especially if your cat has a white nose or ears.


How long do cats with cancer live?

This will depend on the type of cancer they have, how far it has progressed and the type of treatment used. Your vet will be able to give you advice on your cat’s individual condition, so speak to them if you have any worries or concerns about your cat’s prognosis.

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