Monday 16 September 2019

Veterinary oncologists - helping pets with cancer

By Pete Wedderburn - Animal Doctor

I don't like the word "cancer" - it must be the most frightening word of all.

It's no wonder that people sometimes refer to it as "the C word". My preferred term is "tumours", and these can be benign or malignant. And while it's true that a "malignant tumour" is the same as "cancer",  I find that it's a better way to help people understand what's happening with their pets.

'Oncology' is defined as the 'study of tumours', and it is now a speciality in the veterinary world. Tumours can be benign (harmless) as well as malignant. If a pet has an unusual tumour, or a type that requires specialist intervention of any kind, a referral to a veterinary oncologist is now often considered, rather than just dealing with a general vet in practice.

Benign, harmless, tumours - usually small lumps and bumps - are common in pets, and while they may not need any treatment, they should never be ignored. An owner should take any new lump or swelling on their pet seriously, and veterinary advice should always be sought. Common benign tumours include small skin tumours (often resembling "warts") and fatty lumps underneath the surface of the skin. These are found in many older animals, and traditionally, the advice was often to "watch them, but do nothing if they don't change". In recent years, this advice has changed, and it is now often recommended to find out as much as possible about any lump before making a decision on what to do about it.

The simplest investigation is a procedure known as a Fine Needle Aspirate (abbreviated to FNA). This is a painless procedure that can often be done during a normal consultation, without anaesthesia or sedation. A sharp needle (of the same type usually used to give injections) is pushed into the lump, collecting cells in the hub of the needle. These are then squirted onto a microscope slide, and sent to the laboratory. A pathologist stains the slide, and examines it under the microscope. By looking at the cells under magnification, it's usually easy to tell whether they are benign or malignant, and an approximate diagnosis can often be made. An FNA often does not give a definitive and final diagnosis, but it can give enough information to decide on the best course of action. If an FNA result is ambivalent or uncertain, a full biopsy (taken under general anaesthesia) may still be needed.

If an FNA concludes that a lump is benign, then the approach of "watching, but doing nothing unless things change" can safely be taken. As time passes, if benign tumours enlarge, or if they start to change in appearance, the situation needs to be reviewed. It is often safest to ask your local vet to check benign tumours every six months, or at least once a year at the annual health check. Even benign tumours do need to be removed sometimes. Examples include benign tumours of the gums (known as "epulids") which can cause physical difficulties because they start to get in the way of eating, a benign fatty tumour ("lipoma") that gets so big that it starts to interfere with a dog's normal activities, or benign skin tumours that may ulcerate and start to bleed. In each of these cases, surgery to remove the tumours may be needed.

Malignant tumours (which can justifiably be called "cancer") are also common, especially in older animals. Any part of body from the tip of the nose to the tip of the tail, including all of the areas in between, can be affected. Certain malignant tumours are more common in particular subsets of the animal world. For example malignant mammary tumours are the most common form of 'cancer' in un-neutered female dogs. Malignant tumours of the bones of the limbs are common in large or 'giant' breeds like Rottweilers or Irish Wolfhounds. Malignant soft tissue tumours are more common in some specific breeds of dog (eg Flat Coated Retrievers).

Many malignant tumours in pets can now be treated. Some can even be completely cured. Others can be held at bay for months or years, so that animals "die with cancer" rather than "dying of cancer". Treatment protocols originally designed for humans have been adapted to animals, with methods ranging from chemotherapy to irradiation to radical surgery.

Cancer therapy is generally not used as aggressively in animals as in humans, because it would not be humane to allow them to suffer serious side effects from treatment. It would not be considered fair to use treatment that made animals feel seriously unwell, or that would cause all their fur to fall out. It is widely recognised that it is more important for animals to have a good quality of life than to have a slightly longer but uncomfortable life.

The decision 'to treat or not to treat' can be difficult in some cases. The more advanced forms of treatment are expensive. However, for some forms of 'cancer', reasonably priced, effective treatment is now available. It's impossible to generalise: every case is different, and it's always best to discuss the options in detail with the vet that's attending the animal, with a referral to an oncologist as the ideal option.

Tumours - benign and malignant - are most easily treated if they are spotted early. If you find any lumps or bumps on your dog or cat, don't delay: visit your vet sooner rather than later.

Wexford People

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