Month: August 2018

Radio-iodine treatment for thyroid cancer

Thyroid cancer (hyperthyroidism or over-active thyroid gland) is quite common in middle-aged cats. If your cat has been diagnosed with cancer of the thyroid gland there may well be an effective treatment for your pet. The disease can often be successfully treated by surgery but a form of radiotherapy (radio-iodine treatment) is another option and this has fewer complications and a higher success rate than surgery or other forms of treatment.

Radiotherapy uses radiation to damage and destroy cancer cells. The radiation can be administered in a number of ways. However the radiation is given, when it contacts cells it causes permanent damage. In some types of cancer radioactive implants can also be placed in the cancer itself, for treatment of others a beam of radiation is delivered from outside of the body. Cats with cancer of the thyroid gland can be treated with radioactive injections (radio-iodine therapy).

In the treatment of thyroid cancer a radioactive injection is given under the skin. The radioactive material enters the blood and is transported around the body – radiation is concentrated in the cancer cells of the thyroid glands whilst the rest of the body receives a lower dose. The aim with radiotherapy is to give a high dose of radiation to the cancer cells (doing maximum damage) whilst minimising the dose to the rest of the body.

It is quite expensive to have radiotherapy and you will probably have to travel to a specialist centre to get treatment so your vet will not recommend the procedure unless they think it is likely to help in the treatment of your cat. There are many ways of tackling cancer – surgery, drugs (chemotherapy), radiotherapy or often a combination of these. Each type of cancer is best treated in a particular way and if your vet has recommended one form of treatment it is likely that this is the best option for your pet. However, if you are concerned about the treatment then discuss your worries with your vet.

Thyroid cancer is quite common in middle-aged cats. It can often be successfully treated by surgery but this requires a general anaesthetic. Radio-iodine treatment has fewer complications and a higher success rate than surgery or other forms of treatment.

In people the aim of cancer treatment is to kill all cancer cells and cure disease – doses of chemotherapy are therefore high and side-effects such as vomiting and hairloss are relatively common. Although it does sometimes cure cancer the aim of cancer treatment in pets is to prolong a good quality of life (rather than necessarily trying to cure the cancer). This means that treatment sessions are designed to have the maximum beneficial effect without causing side effects. Your pet should remain well throughout the course of treatment.

Radio-iodine treatment is generally the safest method of treating thyroid tumours in cats. However, it is not suitable for cats with other diseases that require regular monitoring and therapy as cats have to remain in isolation during the treatment. People looking after cats receiving radio-iodine therapy cannot handle them while they are radioactive.

In most cats the treatment destroys all the cancer and the disease does not come back. However in a few cats the disease might come back months or years after treatment.

If your pet is having a radioactive injection or implant they will be giving off radiation for the time the radiation is active. Although the dose of radiation is unlikely to be harmful to a healthy person there are long term risks associated with radiation exposure so pets are kept in special areas of the hospital for the duration of treatment. Cats will usually be kept in isolation for 4 weeks, and may have to stay in hospital for longer than this. They will only be released from hospital when it is safe to do so – so you do not need to adopt any special precautions once they come home.

There should be no particular problems once your pet comes home – if you are concerned about any aspect of their health contact your vet for advice. If your pet is receiving medication for other conditions check with your vet that you should continue these throughout the radiotherapy course.

Signs should start to resolve within 2 weeks of injection but a full response may take up to 3 months. Most cats only need one course of treatment but sometimes a second injection is needed.

Cancer of the thyroid gland is relatively common in cats but can usually be easily controlled. It is important that treatment starts early before other damage has occurred in the body.

Lymphoma chemotherapy

Lymphoma is a cancer of the lymph cells and can arise almost anywhere in the body. Lymphoma is one of the most commonly treated forms of the disease. Modern treatment protocols can be highly effective in controlling lymphoma and affected cats can have several years of normal life with appropriate treatment.

Chemotherapy is a highly toxic drug given alone or in combination with other drugs to damage and destroy cancer cells. Chemotherapy drugs can kill all cells (healthy ones as well as cancer cells) and great care is necessary when using them. When treating lymphoma more than one type of chemotherapy is given at the same time the aim of this is to attack the cancer cells from two or more sides whilst minimising the amount of damage to normal tissue by using lower doses of each drug.

Doses are given at intervals (which may be days, weeks or months apart) and during the interval healthy tissue is able to recover and regenerate. Unfortunately in most cases the cancer cells also start to recover and over time the cancer cells often develop a resistance to the drug that is being used for treatment. Treatments must be given regularly so before agreeing to start treatment make sure you are able to give regular medication or can take your pet to hospital for regular treatment sessions as necessary.

There are many chemotherapy treatment plans (also known as protocols) that have been used for the management of lymphoma in cats. The most commonly used include Cyclophosphamide, Vincristine (known as Oncovin) and Prednisolone. This is often called the COP protocol. Sometimes another drug, doxorubicin (also called Hydroxydaunorubicin or Adriamycin), is added and this is called a CHOP or COAP protocol.

Treatment for lymphoma is usually a combination of tablets given at home and hospital visits for your vet to administer some drugs intravenously (directly into the blood stream). Remember that all these drugs are toxic and must be handled carefully. Drugs should always be handled with gloves and must be given according to the schedule prescribed by your vet.

Obviously it is particularly important that these drugs are kept out of the reach of children and pregnant women should not be exposed to them. If you accidently give too many tablets in one dose or give the doses too close together you must contact your vet or veterinary oncologist immediately.

All chemotherapy drugs can cause side effects but these vary depending on the type of drug and the way it works.

Prednisolone

Prednisolone is a steroid but in cancer therapy it is given at very high doses initially. It would be usual for cats receiving prednisolone to drink more than normal and hence wee more often! The drug given to otherwise healthy animals is a potent appetite stimulant. However cats receiving chemotherapy may have a poor appetite due to the cancer or the other chemotherapy drugs and so excessive appetite may not be a problem.

Some cats are more affected by high doses of steroids and may have muscle weakness and show excessive panting. Stomach ulceration is also a potential side effect of high doses of steroids and may cause blood in the vomit or in bowel movements.

Vincristine (Oncovin)

Side effects are rare following treatment with vincristine. The drug is given by your vet into the vein in the leg – if the drug leaks out of the vein it may cause damage and soreness around the site of injection. Weakness and neurological changes are reported by people receiving vincristine but these are rare in domestic pets.

Cyclophosphamide (Cytoxan/Endoxana)

Like many chemotherapy drugs cyclophosphamide can reduce production of white blood cells by the bone marrow, making your pet more prone to infection. This effect usually starts around 1 week after treatment has been given, and reaches its lowest point at 1014 days. The bone marrow should naturally recover and will usually have returned to normal function before the next dose of doxorubicin is due. Your vet will usually check blood samples regularly from your pet to ensure that the bone marrow is working properly.

You should contact your vet straight away if:

  • Your pet has a high temperature (above 38.9°C / 102°F) – if your pet has a fever they will usually be quiet and unwilling to eat
  • Your pet is unwell (even without a high temperature)

Nausea and vomiting have been reported but in most cases this is mild and usually resolves without any treatment.

Hair loss following chemotherapy is not common in dogs. However, poodles and old English sheepdogs may be more at risk. Certainly clipped areas may take longer to regrow if your pet is receiving chemotherapy.

The main problem with cyclophosphamide is the risk of a form of cystitis. This is caused by irritation of the bladder by the chemicals formed when the drug is broken down in the body. To try to prevent cystitis the drug should be given in the morning and the cat should be encouraged to empty their bladder before bedtime. If you see any blood in the urine or your cat shows any signs of cystitis (frequent urination, discomfort on urination, or frequent squatting or straining) do not give any more cyclophosphamide until you have spoken to your vet.

Doxorubicin

Doxorubicin may also affect bone marrow function and you should be alert for signs of infection or anaemia. Doxorubicin can also reduce the production of other cells from the marrow, e.g. platelets (which help the blood to clot). Call your vet if your pet has any unexplained bruising or bleeding, such as nosebleeds, blood spots or bleeding gums.

Nausea can occur within a few hours of treatment with doxorubicin but this can be effectively controlled with drugs. If your cat is reluctant to eat or vomits after treatment make sure your vet knows. If your pet vomits after treatment do not offer them anything more to eat for 12 hours and then offer them a small tempting snack. Ensure that water is available and encourage them to drink if possible. Cats with diarrhoea should be allowed to eat as normal but if you are concerned or the diarrhoea continues for more than 24 hours call your vet for further advice.

Some cats receiving doxorubicin are anorexic after treatment. This may be due to sores in the mouth or in some people the drug alters the taste of food and this may be unpleasant for some animals. Try feeding tempting small meals more frequently to encourage your cat to eat.

Hair loss can also occur after doxorubicin treatment but this is a rare complication and not of any clinical significance.

Lomustine (CCNU)

Lomustine can cause severe suppression of the bone marrow and regular monitoring of blood cell counts is important if your pet is receiving this.

Inappetence, vomiting and/or diarrhoea are also relatively common side effects but these can usually be controlled if the dose is tailored appropriately to the patient.

Many of the chemotherapy drugs have cumulative toxic effects (meaning that the effect of each dose builds up in the body).

Many of the drugs are processed or removed from the body by the liver or kidneys. Your vet may need to check liver and kidney function with regular blood tests, particularly if your pet is receiving drugs which can cause damage to these organs. Lomustine can cause liver damage and permanent bone marrow injury so long term monitoring by blood tests is required.

Doxorubicin can cause damage to the heart muscles and if your pet is receiving this you may be asked to take them for regular ultrasound scans of the heart.

Long term side effects of steroids are not uncommon but these are usually not a significant health risk. Skin may become thinner and darker in colour, hairloss is quite common and cats may develop a pot-bellied appearance.

Lumps and bumps

Finding a lump on your pet can be a worrying experience. Although most lumps are harmless it is impossible to tell what a lump is simply by looking at it. If your pet has a swelling that lasts for more than a few days always ask your vet to check it for you.

There are many different things that can cause swellings: bruising or fluid build-up, abscesses, things attached to the skin, e.g. ticks (small parasites which latch onto your pet and suck blood swelling as they do so), and of course cancers. If you find any unusual lump or swelling on your pet you should make an appointment for your vet to check it out. Although most lumps are harmless, some can be very dangerous if left untreated. The biggest concern for most people is whether their pet has cancer.

Cancers are divided into two groups:

  • Benign: These lumps may grow bigger but do not spread elsewhere.
  • Malignant: More aggressive lumps, which not only grow but also spread through the body and may affect organs such as lungs and liver.

Some benign growths can also cause problems if they continue to grow. Even fatty lumps can grow to a huge size and may cause problems due to their size, e.g. restricting leg movement or pressing on the airways and causing breathing problems. Malignant growths are obviously more worrying – they must be removed before they have spread elsewhere.

Even your vet probably won’t be able to tell whether the lump is cancer, or some other kind of swelling, just by looking at it. There are several things to look for which may help your vet decide whether a lump on your pet is likely to be benign or malignant:

  • If the lump can be picked up in the fingers and moved around it is less likely to be aggressive. Malignant lumps often grow into the tissues beneath the skin and this makes them more difficult to remove.
  • If the lump grows very quickly it can soon cause problems even if it does not spread. Removing a large lump is much more difficult and leaves a bigger wound so fast-growing lumps should be removed while they are still small.
  • Malignant lumps often cause a reaction in the tissue around them – if any lump is red, painful when touched or is ulcerated or discharging then it should probably be removed.
  • Some cancers produce substances that make animals unwell – if your pet has a lump and shows signs of illness e.g. sickness, depression or excessive drinking then mention this to your vet when he examines your pet.

If a lump has been present for a long time without causing any problems it is unlikely to suddenly turn nasty. However, all lumps should be monitored closely. Feel the lump once a month (if you feel it too often you will not notice if it is growing slowly), and keep a note of its size. Ask your vet to measure the lump each year at the time of vaccination and record if it is growing. If the lump changes in any way, i.e. starts to grow more quickly, is sore or discharging, make an appointment for your vet to check the lump again.

If you find a lump on your pet your vet will want to examine the lump to see if they think it is likely to cause a problem. They will also examine your pet to see if they are otherwise healthy or if there are any other growths elsewhere. Unfortunately it will not be possible to say for certain that a growth will never cause problems just by looking at it.

If your vet is concerned they will take some samples from the lump to try to find out what sort of lump it is. Sampling a lump can be as easy as putting a needle into it to collect a few cells or it may be necessary to take a piece of the lump under anaesthetic. These samples can be sent to a pathologist at a laboratory who will be able to tell your vet what kind of lump it is. Once your vet knows this they will be able to advise you on the best treatment for your pet.

In most cases, the only treatment needed for small growths is to remove them. However, if it is a type of cancer that could spread elsewhere your vet may want to make sure that there is no sign of spread and to do this they may need to take X-rays or perform an ultrasound examination. If your pet is old or unwell your vet may want to take a blood sample to check your pet is healthy enough to have an anaesthetic.

In human medicine, skin lumps are often removed by a doctor using a local anaesthetic. It is unusual for this to be done in veterinary medicine. It is very important that the whole of a cancer is removed to make sure that it does not regrow. Even if the lump appears very small it may be necessary to cut quite deeply to remove all of it.

It is important that your pet lies still during the procedure – if they jump or move the operation will be more difficult and dangerous. It is necessary to give patients a sedative to make sure they stay still and sedation is no safer than a well-monitored anaesthetic. Sedated patients may take many hours to recover whereas the effects of a short anaesthetic should wear off more quickly in most animals. If you are worried about treatment of your pet, mention your concerns to your vet who will be happy to discuss all the options with you.

Abscesses

Most lumps on cats are abscesses (usually due to fighting). Often the abscess will need to be opened and drained and antibiotics may be needed.

Fatty lumps

Probably the most common lump found on dogs is a fatty lump (lipoma). These are more common in obese animals. These are benign cancers that rarely spread and are often quite slow growing. However, over many years they can become very large and may need to be removed because they cause physical problems.

Basal cell tumours

These are a type of skin cancer that can occur in cats. They often look like firm round masses about half a cm across. The good news is that most of these are harmless and removal results in cure.

Mast cell tumours (cancer)

These are one of the most common types of lumps found in the skin. Mast cells tumours are a type of cancer that can take on many different appearances and can easily be confused with all sorts of other lumps. Some mast cell tumours are harmless and cause no problems, others are very nasty cancers. It is difficult to tell how a mast cell tumour will behave and they can turn from a benign cancer to a malignant one so all mast cell tumours should be removed.

Injection site swellings

Swelling and discomfort at the site of a recent injection or vaccination is most likely to be due to a reaction in the skin. If swelling develops a long time after injection or continues to grow you must ask your vet for advice. Some cats have been known to develop cancer at the site of some types of vaccination.

Warts

Warts look like small tags of skin. They are more common in older animals. Often animals that have a wart will go on to develop many others. Sometimes warts bleed and may be irritating in which case they will need to be removed.

Mammary tumours (breast cancer)

Lumps in the mammary glands of female dogs are very common and account for nearly half of all cancers in bitches. Most of these are relatively harmless but some of the most aggressive types of cancer can also be found here. Mammary lumps in male animals are often very nasty. Surgical removal of all mammary lumps is advisable and in some cases removal of all mammary tissue (mastectomy) is also necessary. Before removing mammary lumps your vet will want to check your pet thoroughly to make sure that the cancer has not spread anywhere else.

The most important thing to remember is that most lumps, even cancers, can be cured if they are caught early enough – so always check with your vet if you find anything unusual on your pet. In most cases your vet will be able to reassure you.

Feline lymphoma

A diagnosis of cancer is always frightening. One of the most common forms of this disease in cats is lymphoma. This is a cancer of the lymph nodes and can arise almost anywhere in the body. However modern treatment protocols can be highly effective in providing some control of the disease and it is possible for affected cats to have several years of normal life following treatment.

Lymphoma is a cancer of the white blood cells. In cats the disease can take many forms and these are typically distinguished by the area of the body that is affected. Lymphoma affecting some sites such as nasal lymphoma and lymphoma of the cranial mediastinum (tumour in the chest, in front of the heart and between the lungs) is associated with a better outcome. Historically, infection with FeLV has often been associated with an increased risk of lymphoma and leukaemia but this association seems to be declining.

Currently, the most common form of feline lymphoma is the intestinal form. Cats with this type of lymphoma often present with a history of reduced appetite, intermittent vomiting and sometimes a mass can be felt in the abdomen.

Another frequent presentation is cranial mediastinal lymphoma. For an unknown reason cranial mediastinal lymphoma is seen more frequently in young cats, often as young as one year old. The first sign of illness in cats with this form of disease is often severe breathing difficulty.

Kidney lymphoma appears to be a disease of the older cat. The first signs are usually reduced appetite and weight loss. Often an owner identifies a large mass in the abdomen that is actually the enlarged left kidney. These cases invariably have a degree of renal failure and may show excessive drinking and urination.

Cats with nasal lymphoma usually present with sneezing or a discharge from the nose.

Your vet will first want to examine your cat. They may be able to feel a mass in your cat’s abdomen or a thickening of the intestines.

Chest X-rays or ultrasound may be needed to identify the presence of a tumour in the chest or abdomen.

Diagnosis is made by taking a sample of the tumour tissue for examination. This can be done using a fine needle aspirate, core biopsy or surgical biopsy. A sample of the fluid in the chest or some cells from an enlarged kidney can be examined under a microscope.

Multiple treatment options have been described. Currently there appears to be some uncertainty about which is the best type of treatment protocol to use. Two basic protocols are used by most vets, the three drug COP protocols which use the drugs vincristine, cyclophosphamide and prednisolone, and the four drug CHOP protocols which also use the drug doxorubicin. When doxorubicin is used as part of the treatment plan there appears to be a significantly increased risk of gastrointestinal side effects, mostly anorexia. It is unclear whether the addition of doxorubicin adds a real benefit in terms of overall survival.

Your vet will advise you on the best treatment for your cat.

Sadly, there is no cure for lymphoma. Chemotherapy in cats is aimed at providing prolonged high quality life.

There appear to be 3 groups of feline lymphoma patients. Some cases fail to show a good response to any chemotherapy offered. For these patients, their lymphoma is unfortunately fairly rapidly progressive over a few weeks.

Patients in the middle group tend to show a degree of response to the treatment but never achieve complete normality and for these patients there is an average life expectancy of approximately 4 months.

A third group of cats achieve complete remission from their lymphoma and their life expectancy can be measured in years. Cats with fluid in their chest due to a mediastinal lymphoma may appear to be very sick but can be extraordinarily responsive to chemotherapy provided that the initial respiratory complaint can be stabilised.

Whilst cats with kidney lymphoma can respond well to chemotherapy, the significant kidney damage that has inevitably arisen prior to diagnosis persists. This has consequences both in the short and the long term. In the short term, it may be harder for these cats to handle the chemotherapy. In the long term, renal damage is likely to be progressive and therefore, even if the lymphoma enters complete remission, life expectancy can be reduced.

Feline injection site sarcoma

Feline ‘Injection Site Sarcoma’ or ‘Vaccine Associated Fibrosarcoma’ is a rapidly progressive and aggressive cancer affecting cats. The true cause of the disease is not yet understood but it is definitely associated with the administration of long-acting injections like vaccinations. Vaccine technology has advanced since the condition was first reported in October 1991 and effective vaccinations now exist that have not yet been associated with this condition. Rapid appropriate action is required to give patients with this condition the best chance of a lengthy remission or cure.

Feline ‘Injection Site Sarcoma’ or ‘Vaccine Associated Fibrosarcoma’ is a rapidly progressive and aggressive cancer affecting cats. The true cause of the disease is not yet understood but it is definitely associated with the administration of long-acting injections like vaccinations.

Injection site sarcomas can develop in cats of almost any age – usually months or years after vaccination. They typically occur at the base of the neck between the shoulder blades as this is the site most commonly used for injection in cats. However, they may develop at any site where an injection has been given.

Usually the mass if the first sign noticed before the animal becomes ill in any other way.

If you detect a swelling under the skin in your cat at a site where they have previously had an injection seek veterinary attention straight away (within the following two days). Your vet will evaluate and measure the lump.

Lump larger than 1cm

If the lump is larger than 1cm across or appears to be rapidly growing ask your vet to contact a veterinary oncologist to get up-to-date advice on treatment. For rapidly growing or larger lesions it is recommended that an incisional biopsy is taken in all cases. Attempted removal without knowing the true nature of the lump can foil all chances of a long term remission.

Lump smaller than 1cm

If the lump is less than 1cm or appears not to be rapidly growing it may be assessed again 1 month later. If at follow up examination it is apparent that the lump is not growing, continue monthly checks for 3 months in total. After this time decisions can be made between you and your vet about the most appropriate way to proceed, this may involve biopsy or removal of the lump.

It is generally well recognised by veterinary oncologists that surgery offers the best chance of long term control. However, this surgery must be performed by an appropriately trained soft tissue surgeon and it is likely that your cat would need to be referred to a specialist centre to get the most effective treatment.

Specialist oncologists may offer a combination therapy approach which harnesses the benefits of both chemotherapy and surgery to provide a dramatically improved outcome for the patients concerned. Unfortunately, this treatment strategy is not appropriate for all patients. It is important that patients are fully evaluated first to ensure that treatment is not prescribed to patients that would not ultimately benefit from the treatment plan offered. As always, the goal of therapy is first and foremost to extend a good quality of life, not to attempt to extend life at all costs.

Chemotherapy: safe handling

Chemotherapy is now a commonplace treatment for cancer in pets. In many people’s mind the term ‘chemotherapy’ conjures up frightening images of people suffering with cancer (and the effects of treatment) – however chemotherapy in pets is usually very different.

Chemotherapy is a highly toxic drug given alone, or in combination with other drugs, to damage and destroy cancer cells. Chemotherapy drugs can kill all cells (healthy ones as well as cancer cells) and great care is necessary when using them. Many vets in practice will refer patients to specialist veterinary oncologists when chemotherapy is being considered.

All chemotherapy drugs are toxic and should not be taken unnecessarily. However, it is important to get the risks into proportion and not to be afraid of managing your pet at home. Whilst the drugs can cause many side effects these are usually seen with large doses or long term use.

If your pet is taking a tablet and you touch that tablet the amount on your hands is unlikely to cause you any side effects even if you put your fingers in your mouth. However, many of the cancer treating drugs can cause cells to mutate. It is essential that pregnant women do not come into contact with these drugs as damage can be done to the foetus. Drugs causing DNA mutations can also cause normal cells to become cancerous.

Some chemotherapy drugs are irritant and can cause reactions or allergies in the skin if touched.

Often you will be asked to give tablets to your pet at home. It is important the drugs are given at regular intervals according to set treatment plans (protocols). Before your pet starts on treatment your vet will need to be sure that you are able to give the drugs regularly and to follow instructions regarding their use.

If you are really concerned about giving treatment at home, share your concerns with your vet. It may be that there is an alternative treatment that your vet can administer for you. These will have to be given in the veterinary hospital and you will need to take your pet for regular treatment appointments.

Many of the drugs can be given with food. Your vet will advise you on the best time and method of giving the drugs. If you give the drug with food always handle them with gloves and put in a small amount of tasty food (that you can be sure your dog will want to eat) in a small dish.

Watch your cat to make sure they eat the food and all of the tablets and then make sure that they do not spit the tablet out again afterwards. The bowl can then be washed up separately before giving your cat the rest of his food.

If you are doubtful whether your pet can be relied on to eat the tablets with food it may be safer to put the tablets straight down the throat. If you do this it is even more important to wear gloves as the protective coating put on some tablets can be dissolved by saliva in your cat’s mouth. If you have not given tablets to your pet before ask your vet to show you how to do this safely and effectively.

Your vet will not allow your pet to go home with you if there are any risks to you from your cat. It is perfectly safe to continue to treat your pet as part of the family and hugging and petting are all permitted. The risks to you come from exposure to the drug itself. Remember also that the drugs are removed from the body in urine and faeces so there is a potential second risk of exposure.

There is some debate over how long pets can excrete chemotherapy drugs and metabolites in their urine and faeces. Therefore it is sensible to avoid direct contact with waste from your pet while they are receiving chemotherapy.

Once a treatment course has finished, you should maintain the same strict measures that you followed during treatment for a further three weeks. If your cat is having tablets or capsules there may be a risk of exposure to the drugs in these if your cat vomits after treatment. Ensure that you wear protective gloves to clear up any vomit and place all the cloths used for cleaning and gloves in a tied plastic bag with the vomit and place straight in an outside dustbin.

Chemotherapy for your cat

Although it can be frightening to learn that your pet has cancer there have been big advances in the treatment of cancer in animals. Chemotherapy is now a commonplace treatment for cancer in pets. If your cat is diagnosed with cancer it is possible that you will be offered some form of chemotherapy (perhaps alongside surgery or radiation therapy).

Chemotherapy is the use of drugs to damage and destroy cancer cells. Chemotherapy drugs can kill all cells (healthy ones as well as cancer cells) and great care is necessary when using them. There are many types of chemotherapy and depending on the drug they can be given by mouth, directly onto the lesion or given by injection into a body space or directly into the blood stream.

Different chemotherapy drugs are more effective against specific types of cancer and it is essential to get an accurate diagnosis of the type of cancer before the appropriate drug can be selected for treatment. Many vets in practice will refer patients to specialist veterinary oncologists when chemotherapy is being considered.

Chemotherapy is just a highly toxic drug given alone or in combination with other drugs. Your vet will try to find a treatment that is particularly toxic to a given type of cancer cell but less so to normal healthy body tissue.

Chemotherapy is given at a dose that will kill as many cancer cells as possible without doing too much damage to normal tissue. Doses are given at intervals (which may be days, weeks or months apart) and during the interval healthy tissue is able to recover and regenerate. Unfortunately in most cases the cancer cells also start to recover and over time the cancer cells often develop a resistance to the drug that is being used for treatment.

Often more than one type of chemotherapy is given at the same time – the aim of this is to attack the cancer cells from two or more sides whilst minimising the amount of damage to normal tissue by using lower doses of each drug.

Cancers can be treated using a variety of therapies (surgery, radiation or chemotherapy) and often a combination of treatments is given. If your vet has recommended chemotherapy it will be because it is the most effective treatment for your pet. You may need to travel to a specialist oncology centre for treatment and some forms of chemotherapy are expensive, therefore it is important that you discuss all your concerns with your vet before treatment starts.

It is very important that if you begin a course of treatment that you are able to see it through to the end. Treatments must be given regularly so before agreeing to start treatment make sure you are able to give regular medication or can take your pet to hospital for regular treatment sessions as necessary.

In some cases you may be given tablets to give your pet at home. Remember that these drugs are potentially toxic and must be handled according to the instructions given by your vet. Drugs should always be handled with gloves and must be given according to the schedule prescribed by your vet. Obviously it is particularly important that these drugs are kept out of the reach of children and pregnant women should not be exposed to them. Other drugs have to be given by your vet in the veterinary hospital and you will need to take your pet for regular treatment appointments.

Chemotherapy protocols are carefully designed to maximise the beneficial effect and minimise side effects of the drugs. The drugs are given regularly with an interval that allows healthy tissue to recover between doses. It is therefore important that doses are not given too close together or too much damage can be done to healthy tissues. If you accidently give too many tablets in one dose or give the doses too close together you must contact your vet or veterinary oncologist immediately.

Everyone has heard stories of how unwell some people are whilst receiving chemotherapy and no-one wants this for their pet. However, there is a difference between human and veterinary medicine. In human medicine doctors are aiming to prolong life for as long as possible – this means that treatment in people is often very aggressive (high doses of drugs are used to kill the maximum numbers of cancer cells). The high dose of drugs used makes the side effects much worse. In veterinary medicine vets are trying to prolong only high quality life. In general doses of treatment are calculated to minimise any ill effects experienced by your pet.

All chemotherapy drugs can cause side effects but these vary depending on the type of drug and the way it works. Hair loss, a well-recognised (and much feared) problem in people, is rare in animals receiving chemotherapy. However, clipped hair may take longer to regrow and the texture of the hair coat may change. Many cats receiving chemotherapy will be given steroids as well; these typically have side effects of increased drinking and urinating.

Commonly, chemotherapy can cause damage to the bone marrow which may make animals anaemic or suppress their immune response. For this reason pets receiving chemotherapy are usually closely monitored with regular blood tests to monitor levels of blood cells.

Digestive system upsets (nausea with or without vomiting and diarrhoea) are caused by damage to cells lining the intestine. Effects can range from extremely mild diarrhoea to severe vomiting and bloody diarrhoea. In most cases these complications are short lived and can be managed quite simply with the use of drugs to control sickness. However it is very important to report such complications to your vet so that they can provide you with additional treatment and it may be necessary to reduce the dose of the chemotherapy to prevent these complications occurring after the next dose.

If you are concerned in any way about your cat’s health you should contact your vet immediately.

Many of the chemotherapy drugs have cumulative toxic effects (that means that the effect of each dose builds up in the body). Many of the drugs are processed or removed from the body by the liver or kidneys. Your vet may need to check liver and kidney function with regular blood tests, particularly if your pet is receiving drugs which can cause damage to these organs. One commonly used chemotherapy drug can cause damage to the heart muscles and if your pet is receiving this you may be asked to take them for regular ultrasound scans of the heart.

Cancer in your cat – possible options

Cancer is the uncontrolled growth of abnormal cells. The speed with which a cancer spreads and the severity of the disease it causes depends on the type of tissue cell affected. As many as one in five cats are likely to develop one of the many different forms of cancer at some stage of their lives. The risk of developing cancer increases with age. This means that, as cats now enjoy a longer life expectancy through improved veterinary care, the number of animals with cancer has been increasing in recent years.

As with human cancers, the causes of cancer in cats are still not well understood. Possible causes include:

  • Toxic chemicals or exposure to harmful radiation.
  • Feline leukaemia virus (a very common cause in cats).
  • Abnormalities in the immune system that usually protects against infectious diseases.
  • Abnormal genes.

The signs of cancer are very variable and depend on the type of tissue cells involved, the site of the cancer and the stage of the disease. Animals with advanced cancer often show weight loss and loss of appetite. Your cat may be depressed, vomit, have diarrhoea or constipation, or fever. Your cat may also get tired easily because of anaemia. You might also find an unusual lump or swelling on your pet, if so, you should make an appointment for your vet to check it out. Although most lumps are harmless, some can be very dangerous if left untreated.

Cancer can occur in any animal at any age but certain types of cat are more susceptible to particular forms of cancer. Cats with white fur and skin that like to sunbathe are vulnerable to skin cancers especially on the ears, nose, lips and any other areas where the skin is exposed to direct sunlight. The risk of cancer developing may be reduced by applying sunscreen to areas of exposed white skin/hair on sunny days.

Feline leukaemia virus is the most common cause of cancer in the cat, although not all cats exposed to the virus will develop the disease. Most cats are able to resist the virus but those that cannot, will develop permanent infection and 3 out of 10 of these will get some form of cancer.

Yes, most forms of cancer can be treated, but this depends on the type of cancer involved and whether the disease has spread. The outcome of treatment can be very variable. In some cases treatment can produce a complete cure, or at least significantly increase the length or improve the quality of your cat’s life. Sometimes euthanasia is the only humane alternative to a slow and painful death.

There are three basic options for treating cancers; not all are appropriate for every case and sometimes a combination of treatments has the best chance of success. The treatment options are:

Surgical removal

Usually the best choice for most cancers of solid tissue. If the cancer is relatively benign, or if a more malignant cancer has not yet spread to other parts of the body, surgical removal often produces very good results.

Chemotherapy (drug treatment)

Chemotherapy is the best option for cancers affecting the blood or multiple areas of the body. Drug treatment may also prevent or delay the appearance of secondary tumours in other organs after surgical removal of the original lump. Chemotherapy is used to improve quality of life in pets and the side-effects of chemotherapy seen in people are usually not seen in cats.

Radiotherapy (x-rays)

Radiotherapy is often effective when tests have clearly shown the extent and size of the tumour. The radiation is usually delivered by a special machine in a radiotherapy unit. A beam of radiation is most effective on cancers of the extremities (such as the limbs and head) where it is less likely to damage normal tissue before reaching the tumour.

Radiotherapy units are only located in a few specialised centres and your vet would need to refer you to a cancer specialist for this form of treatment. In some cases it may be possible to treat the cancer by injecting radioactive material into the body.

Discomfort can be severe when the cancer is advanced, but most cancer-related pain can be controlled. Your vet will probably try a gentle painkiller at first and move on to more powerful drugs if these are required. Your vet will try to improve your cat’s quality of life rather than prolonging the life of your cat if it is suffering.

Careful attention to your cat’s diet may improve its quality of life. Cats need extra food to cope with the effects of a fast growing tumour but many cancer patients have a poor appetite and so lose weight. Warming the food or feeding by hand may help stimulate your cat to eat. There are also special diets designed for animals with cancer which provide good nutrition even if your cat’s appetite is poor.

This is the question that every owner wants answered but as with human cancer it is impossible for your vet to give you an answer with any confidence. The survival chances will depend not only on the type and stage of the disease but also on your cat’s general state of health. You should discuss this issue with your own vet so that you can agree between you an appropriate treatment plan for your cat.

It is understandable that, faced with a diagnosis of cancer, you will feel frightened about the future for your pet – discussing your fears with your vet is the very best way to obtain reassurance and an independent assessment that you are doing what is right for your pet.

Feline Infectious Anaemia (FIA)

Feline infectious anaemia, also known as FIA, is an anaemia in cats that is caused by a parasite that lives in the blood. If your cat is unwell and pale, it may be that it is anaemic, but there are many different causes of anaemia in cats and FIA is just one of these. Early recognition and treatment of FIA is important to maximise the chances of full recovery.

There are a number of infections (e.g. Babesia felis in South Africa) that can result in anaemia in the cat, but FIA typically refers to anaemia caused by parasites called ‘haemoplasmas’.

Haemoplasmas are bacteria that live on the surface of red blood cells. Several different haemoplasma species infect cats. Mycoplasma haemofelis (also called the large strain) is the most important haemoplasma as it causes the most severe anaemia in cats. Other haemoplasma species tend to cause less disease in cats: ‘Candidatus Mycoplasma haemominutum’ (also called the small strain) and ‘Candidatus Mycoplasma turicensis’.

When the red blood cell is infected with the haemoplasma parasite it does not survive long in the circulation. The parasite can cause damage to the membrane surrounding the red cell, causing the cell to rupture. Affected blood cells may also be destroyed by the body and, as numbers of circulating red blood cells drop, anaemia develops.

The natural method of haemoplasma transmission has not yet been proven. Fleas are thought to be able to spread infection, so flea bites may transmit infection to your cat. Infected blood transfusions have also been found to spread infection.

It may be that aggressive cat bites transmit infection since haemoplasmas are found in the saliva, but transmission this way isn’t always thought to be very effective. It is known that male cats are more likely to be affected than females which may be the result of their lifestyle and increased risk of fighting. Very young kittens can be infected from contact with their infected mother.

Cats may be more at risk of getting anaemia due to haemoplasma infection if their immune response is reduced. This can occur in cats that are ill with other diseases or cancer. Some drugs (e.g. treatments for cancer) and infections like FeLV and FIV also suppress the immune response and can put cats more at risk from infectious anaemia.

Cats are very good at hiding signs of illness, especially anaemia, so it is possible that you won’t recognise signs of anaemia in your cat until the anaemia is very severe.

Cats with anaemia are generally depressed, lethargic and their appetite may be reduced. The membranes inside their mouth and eyes may appear paler than normal, or sometimes these membranes and the eyes take on a yellowish tinge due to jaundice (as a result of excessive red cell breakdown).

Severely affected cats may have breathing problems and become breathless even after minimal exercise. Cats with infectious anaemia often have a high temperature too, and they often become quite markedly dehydrated as they stop eating and drinking.

Your vet will examine your cat and may be suspicious that it is anaemic from the examination. It will be necessary to take blood samples to confirm the anaemia. If anaemia is found then further tests, such as X-rays and ultrasound, may be required to look for possible causes of anaemia.

Further samples of blood may need to be sent away to get final confirmation of the presence of haemoplasma parasites in the blood. Because of the association between infectious anaemia and other disease such as cancer and FeLV/FIV your vet will probably also want to do other tests to find out if any of these conditions is present in your cat.

The parasites can be killed with antibiotics. Cats usually show quite a rapid response to treatment in terms of improvement in clinical signs, but a longer course (up to 8 weeks) of antibiotics may be required to try and maximise the chances of your cat getting rid of the infection completely.

Additionally, if your cat is very severely affected with profound anaemia, they may need to be hospitalised for emergency treatment such as a blood transfusion, intravenous fluids and/or nutritional support.

Unfortunately infection persists in some cats despite long courses of antibiotics, but they usually don’t show any signs of disease; these cats are called carrier cats. Longer antibiotic treatment courses try to eliminate this carrier status, but it is not always possible.

Following treatment your cat may appear to be quite well again but there is always the potential for a stressful trigger to result in the disease returning in carrier cats, although this is probably not that common.

It is important to control fleas in all cats as fleas are thought to be involved in transmission. Generally the outlook for your cat is good if they do not have any underlying diseases.

Urine samples: how to collect

Tests are used by vets to help them diagnose disease in animals that are ill, which means your vet may ask you to bring in a urine sample (water sample) from your pet to help find out what’s wrong with your cat. Urine samples are usually taken to check for diseases such as diabetes or cystitis. Urine samples are also often used as part of a routine health check to detect hidden disease before the development of obvious symptoms; this allows your pet to be treated earlier and more effectively.

The best sample is a mid-stream sample (a urine sample) collected by placing a suitable container (a small bowl or dish) under the stream of urine whilst your pet wees. However this is almost always extremely difficult to do in cats. You may be able to catch your cat out by using a long handled collecting pot. Attach a pot, for example a clean yoghurt carton, to a stick or broom handle using sticky tape. Once your cat starts to wee, move the carton under the stream of urine to collect the sample.

It is important not to use jars that have previously contained jam or honey as these can affect the test results.

In most cases your vet will only need a few teaspoons of urine to perform all the tests. If a larger sample is needed your vet will tell you.

Often the only way to collect a sample from a cat is to allow it to wee in peace in a tray and then collect the sample from the tray. Place some non-absorbent cat litter (glass beads or fish tank gravel) in the clean and dry litter tray and confine your cat in a room with the tray. Once your cat has used the tray suck up some urine from the tray with a pipette or a syringe and squirt it into a pot for storage. When you take the sample to the vet always tell them how you collected the sample as this may affect the tests your vet can do.

Some cats are extremely unwilling to wee anywhere except outside. If you really cannot get a urine sample your vet will probably suggest that they take your pet into the hospital and collect the sample for you. Samples can be collected directly from the bladder using a catheter passed up the urethra or via a needle placed into the bladder through the stomach wall. Both these procedures are simple and carry few risks for your pet.

Pour the sample into a clean, screw-topped container; write your cat’s name, your name and address and the date the sample was taken on the jar. If you can’t take the sample to the vets immediately, it is best to store it in the fridge for a maximum of 12 hours.