Facts About Cancer in Cats

Are you a glass half-empty or a half-full person?

When it comes to cancer in cats there’s good news and there’s bad news.

First the good news:

• Cancer is less common in cats than dogs; half as likely to happen, to be precise.

And the bad news:

• When cancer does develop it tends to be more serious.
• Cat cancers are three to four times more likely to be malignant than cancer in dogs.

In reality this means you should be vigilant for any hints or clues that your cat is unwell, because catching cancer early makes all the difference to the success of treatment. But before we get ahead of ourselves, let’s look at the facts about what cancer is and how it affects cats.

What is Cancer?

Cancer occurs when cells in the body grow and divide without control. Any tissue with the potential to grow can become cancerous. If that tissue is solid (such as skin, bone, or lymph node) the cancer is called a tumour.

Next let’s look at benign versus malignant cancers. When a cancer diagnosis is made the vet will investigate if it’s benign or malignant. This is an important difference to understand because it has implications for treatment and the long term future.

• Benign: These are discrete, lumps that are usually slow growing and may cause a local problem but don’t spread to other parts of the body. Surgical removal of benign lumps may well be curative. [A brief digression: Hyperthyroidism is caused by a benign tumour of the thyroid gland, which then produces too much hormone.]
• Malignant: These are more aggressive and invade healthy tissue, including other parts of the body (this is known as ‘metastases and are a serious development) Malignant cancers are difficult to treat and chemotherapy may be necessary to try to bring the condition under control.

Commonest Cancers in Cats

Cats are most likely to develop cancer of:

• The skin: a cancer to be especially cautious about is sun damage on the nose and ear tips of white cats. This can induce a skin cancer known as squamous cell carcinoma.
• Blood: Leukaemia is where the bone marrow produces too many of one type of blood cell. You may be familiar with this from feline leukaemia, which is where a virus triggers the replication of cells in the bone marrow which are then released into the circulation.
• Mouth: Malignant melanoma is a black-pigmented cancer that can affect the gums and lining of the mouth.
• Stomach and Gut: Cats are prone to lymphoma of the bowel, where the gut wall soaks up cancerous white cells.
• Mammary Glands: Unfortunately breast cancers in cats carry an 80 – 90 % risk of malignancy. However, desexing at an early age reduces the risk of breast cancer occurring.

Signs of Cancer

Early diagnosis and treatment gives your cat the best chance of recovery; so what signs should you look for?

They symptoms are often quite general and include:

• Changes in thirst, such as drinking more
• Persistent sickness or diarrhoea
• Changes in appetite, especially loss of interest in food
• Sore or inflamed ear tips or nose
• Skin lumps or bumps
• Weight loss

As a rule of thumb if you notice any change from the norm it’s best to get your cat checked by a vet, (and not just because of cancer.)

Reducing the Risk

In many ways cancer in cats is similar to humans, in that there’s either a genetic link to cancer or it can just be “one of those things”.

It always helps to feed a healthy diet and minimise stress since this promotes a strong immune system, which is the cat’s best defence mechanism. Other things to consider include:

• Sun exposure: Keep white cats out of the sun, and if they’re real sun worshippers apply pet-safe sun cream to the nose and ear tips (and hope it doesn’t get washed off!)
• Vaccination: The feline leukaemia vaccine has made a huge, positive impact on reducing the prevalence of this deadly disease. Twenty years ago it used to be the case that four out of every five UK cats were exposed to the virus at some point in their life (of course, not all of these cats became ill). Now, it’s relatively rare for them to contact the virus, because so many cats are vaccinated. But if your cat has close contact with others, then vaccination is essential.
• Desexing: This reduces the risk of breast cancer in females.
• Regular Skin Checks: Once a week, give your cat a fingertip massage and check over their body for new lumps and bumps. If you find something in the early stage your vet is in a strong position to completely remove it.
• Avoid Chemicals and Smoke: Contact with strong chemicals and cigarette smoke is never a good idea as these are carcinogens.

How Does My Vet Diagnose Cancer?

Your vet will examine the cat to check to see if the lump is localised or if lymph nodes are involved. Blood tests don’t diagnose cancer but they are necessary to check the health of the immune system and to work out how healthy the liver and kidneys are. The latter is important if an anaesthetic or chemotherapy is on the cards.

If a solid tumour is present the vet may either biopsy it or take a fine needle aspirate to obtain a small sample of cells. An expert then looks under the microscope to put a name to the cancer. In addition, the vet may want to stage the cancer, which means an ultrasound scan or radiographs to look for signs of spread.

How is Cancer in Cats Treated?

This depends on the type of cancer. Cancers affecting the immune system such as leukaemia and lymphoma are usually treated with low doses of chemotherapy drugs. Whilst this sounds alarming, the doses used are reduced because the aim is to give the cat an extended period of good quality life rather than a complete cure, which avoids side effects such as fur loss.

Solid tumours may be surgically removed or in some cases blitzed with radiotherapy.

And finally, how you view cancer in cats depends if you are a glass half-full or half-empty person. On the one hand you can relax because cancer is less common in the cat, but on the other the condition needs prompt detection and treatment for the best possible outcome.