Cancer in Cats

Like humans with every passing year our cats are increasingly likely to suffer from diseases of old age, including cancer.

We’re still not sure about the exact cause of cancer in cats but many veterinary scientists now think the feline leukaemia virus is a major contributor, although factors such as environmental toxins including second-hand smoke seem to have a part to play.

Certainly, a healthy lifestyle, diet and regular wellness check-ups with your vet can help to prevent cancer in cats but a cancer diagnosis need not be a death sentence if symptoms are spotted early.

Common Symptoms of Cancer in Cats and Types of Cancer

These basal cell tumours are a type of cat skin cancer but are thankfully quite rare. They’re usually seen around the neck, head, ears and shoulders, forming as solid lumps beneath the skin, however they are mostly benign.
Another relatively uncommon skin cancer, Mast Cell tumours appear as pigmented, ulcerated nodules. They can be found anywhere on the body and can only be properly diagnosed with a biopsy carried out by your vet.
These tumours appear in the fibrous tissue just under the skin as solid, irregular masses. Like Mast Cell, biopsy is the most reliable diagnostic tool.
Lymphosarcoma (LSA) is common among cats who have suffered feline leukaemia virus infections and because it affects the intestines and other lymphatic tissues in the abdomen, symptoms commonly include lost appetite and weight loss, vomiting, diarrhoea, blood in faeces and/or constipation.
Symptoms are usually related to respiratory system and may include difficult or rapid breathing and coughing up blood, but these are surprisingly uncommon. Left undiagnosed and untreated however, the cancer can grow rapidly and metastasize – spread – to brain, eyes, bones, and other organs, showing up in low energy, poor appetite and weight loss, muscle wasting and lameness. Diagnosis can be difficult because tumours must be a certain size before they show up clearly on any X-ray and a biopsy is again the only real way to confirm the disease.
While a brain tumour in cats is less common than in dogs, it seems to be older toms who are at the highest risk, with benign tumours growing in the membranes which cover the brain. The single most common symptom is seizures – which you should react to whenever they occur – but also watch out for abnormal behaviour, changes in habits or routine, head pressing, heightened sensitivity to pain or to being touched around the neck, bumping into things and sight issues. He may also vocalise more yet purr less. Your vet will use blood and urine tests, possibly coupled with an X-ray to confirm a diagnosis, and treatment, outcome usually depends on the position and type of tumour and its stage.
Once again, older males are at the most significant risk of Liver Cancer in Cats and, like Lymphoma, because of the of the connection with digestive system, symptoms can include vomiting, loss of appetite, weight loss, nausea and diarrhoea. But because the liver is involved in many other bodily processes, you should also watch out for symptoms common to many the cancers we have discussed so far, as well as pale gums and jaundice. Proper diagnosis requires blood and urine tests and a liver needle biopsy carried out under a general anaesthetic. Because of the liver’s astounding regenerative power, up to three-quarters of the organ can be safely removed to eliminate the tumour. If the cancer has not spread to other parts of the body, surgery is normally successful.
There is no single proven cause of mouth cancer in cats; however, research has shown that they may be at more serious risk if you smoke, they eat large amounts of canned food – especially containing Tuna – or they routinely wear a flea collar. Some mouth cancers show up as visible lumps, but other squamous cell carcinoma tumours are harder to spot, growing invisibly inside the tongue, tonsils or roof or back of the mouth. Common tell-tales include bloody nose or mouth, oral pain, loose or lost teeth or facial swelling. The earliest symptoms might be bad breath, difficulties eating and drinking (and resulting gradual weight loss) as well as increased salivation. Mouth cancer can be very aggressive and quickly spread to the lungs and lymph nodes, so aside from the usual blood tests and biopsies, you vet may well request a CT scan (if available) to check for other tumours within the upper body. While mouth cancer may appear to be easy to get to, successful treatment usually includes removal of bone which may be impossible in parts of the mouth, so your vet may suggest radio- or chemotherapy.

Does my Cat Have Cancer? Symptoms of Cancer in Cats

When vets talk about cancer the terminology can get confusing because they use different words for the same thing. This is often because in the process of trying to work out what might be wrong with your cat they initially need to consider a wide range of potential problems and don’t want to be too specific too early. Words like growth, tumour, mass and neoplasia all roughly mean the same thing; one, or part, of the tissues of the body has started to grow or enlarge out of step with the rest. This might cause a lump or swelling which you can see or feel or might be happening internally with little indication, especially in the early stages, that anything is changing.

Some of these growths or tumours are ‘benign’, which means that they aren’t likely to keep on growing or spreading to the point that they will endanger life. Many of us will develop some sort of benign tumour in our lifetime and although they may need to be dealt with they probably won’t cause us a huge problem. What scares most of us are the other types of tumour, the ‘malignant’ tumour, more commonly known as ‘cancer’. What makes these tumours different is that they will keep on growing and spreading to such an extent that they can be fatal.

If your cat has a lump, swelling or particular set of symptoms and the vet suspects a tumour the first question to try and answer is whether its benign or malignant. This usually requires a sample of the lump, or tissue that appears to be affected, called a ‘biopsy’, is taken and sent to a specialised laboratory for examination. Diagnosing which specific type of tumour your cat has is not always straightforward. Taking a biopsy often requires an anaesthetic and the part of the body being sampled isn’t always easy to access or might be in the middle of some delicate and vital parts of the body. X-rays, ultrasound scans or a CT scan may also be used to visualise where and what a tumour is.

Just about anywhere in the body can be affected by tumours; skin, bone, liver, mammary glands, brain. Common types of cancer in cats affect the skin, mouth and the immune system. The immune system cancers, usually called ‘lymphoma’, are probably the most common in the UK. When lymphoma develops, a type of White Blood Cell (WBC), which usually circulates round the body and helps to fight infection, changes or ‘mutates’, and starts to invade different parts of the body. A common place for these abnormal cells to invade would be the ‘lymph nodes’, which are collections of WBC’s dotted around the body ready to deal with any threat of infection. Usually these lymph nodes are hard to feel but if they become infiltrated by abnormal WBC’s they become enlarged and more prominent. Some lymph nodes are near the outside of the body, like the ones in the neck or back leg but others are tucked away deep inside the body and can only be seen using scans or exploratory surgery. Another common place for these mutated WBC’s to affect is the gut, either causing tumours or accumulating along the intestinal wall causing it to thicken and work less effectively.

Treating Cancer in Cats

There is treatment available for some cancers in cats but it is usually better looked at as a way of slowing down the disease rather than achieving a ‘cure’. Research into feline cancer is nowhere near as advanced as it is for people and the resources required would be out of reach for the vast majority of pet owners. There are also ethical issues around putting animals through the sometimes highly unpleasant cancer treatments which people can decide for themselves to undertake.

Some types of tumour can be removed by surgery (cutting out the cancer while your cat is under anaesthetic). This depends on what type of tumour it is, how big it is and where it is in the body. If a tumour is very close to other important structures, or in a place where there is very little spare skin to close over the surgical wound then surgery might end up actually making your cat’s problems worse.

Other cancers are better treated with medication, also called ‘chemotherapy’. While this may conjure up worrying images of people being made very unwell during their cancer treatment we don’t push animals to these extremes of chemotherapy. There are courses of drugs we can use, called ‘protocols’, which aim to shrink cancers and slow down their growth. Vets who specialise in treating cancer in pets have devised different protocols for different types of cancer. Most protocols will involve tablets and injections and monitoring with blood tests. There may be side effects but if these are significant then its likely the treatment will be stopped.

You and your vet will need to decide on how best to deal with your cat’s cancer. In addition to the type of cancer being treated you have to consider your cat’s nature and potential response to frequent medication and visits to the vet. Will you be able to give your cat tablets, possibly every day for months? Does your cat get distressed while being transported or held for blood tests? Some cats take it all in their stride but others may fight against the help you’re trying to give.

Caring for a Cat With Cancer and Life Expectancy

If your cat has been diagnosed with cancer you are likely to have lots of questions about how best to deal with it and what the future holds. While your vet can give you the options you have for treatment it may be more difficult for them to give you an accurate timeline of how your cat’s disease will progress. Its famously difficult to predict ‘how long they have left’ for anyone and with cats and their private, sometimes unpredictable, natures its even harder. Cancer doesn’t always follow the text book and your cat may not either.

We all want to do what we can to make sure our pets are not in pain and feel well enough to enjoy life. Assessing pain in cats requires knowledge of their unique behaviour and appreciation that they don’t necessarily show that they are experiencing it. Their type of cancer will give us some indication of how likely it is to be painful. They might spend a lot of time asleep, but perhaps they are just lying quietly in the hope that the pain subsides. Some cats will become withdrawn or sit in uncharacteristic poses or positions.

Your vet may discuss palliative care for your cat, either if treatment is not an option or if the treatment your cat has been receiving is no longer working. Palliative care is treatment which aims to address the pain and discomfort caused by a disease rather than change the course of that disease. This is likely to include pain killers or steroids which can temporarily make cats feel better and more like eating.

Obviously as a minimum cats need to eat and be able to go outside or use a litter tray for toileting. If they are unable to do this or your cat becomes very unwell or experiences unpleasant symptoms you will probably have to make a decision about how long you will let that continue even if its sooner than you were expecting. If treatment, whether palliative or not, is no longer helping then you will need to consider cat euthanasia.