Cancer - diagnosis and treatment
Diagnosis
A positive diagnosis of cancer in your cat is not a death sentence. Many cancers can be surgically removed, and even malignant cancers can be treated to some extent. Though more common in elderly animals cancer may strike a cat at any stage in her life.
| It is important that cancers are detected as early as possible. The quicker the cancer is found, the better the cat's chances. Diagnosis is not easy and requires different techniques depending on where the cancer is located. Often multiple tests are required before a definite diagnosis can be made. Below we have included a list of the most common diagnostic tools: |
Blood test - a blood test is useful in diagnosing cancers such as leukemia. It is also used to detect secondary problems such as bacterial infection, anemia and the side effects of cancer treatment.
Cytology - this is based on analyzing cells from a tumour under a microscope. This helps, for example, in diagnosing skin cancers or lymphomas. This procedure is relatively straightforward and often does not even require anaesthetic.
Radiography (X-ray) - looks inside the body and will reveal deformities in organs that cannot be felt. It is normally the first test done, and most veterinary clinics can do this. X-ray is particularly good for detecting bone cancers.
Biopsy - removal of larger piece of solid tissue for microscopic analysis. Biopsy is often used to diagnose solid tumours when extracting cells with a fine needle is not possible or when the original cytology test did not produce a conclusive result.
Ultrasound - is a technique which used sound waves to show the internal structure of soft tissues. It can detect abnormalities deep within the tissues. It is also used as a complementary technique, helping to guide the needle into the tumour during biopsy or cell extraction.
Endoscopy - is the examination of the inside of the body using a lighted, flexible instrument called an endoscope. In general, an endoscope is placed into the body through a natural opening such as the mouth or anus. The most common endoscopic procedures evaluate the esophagus (connecting throat and stomach), stomach, and portions of the intestine, and colon.
CT ( computerised topography) scan - pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them in pictures. A CT scan can reveal some soft-tissue and other structures that cannot be seen in conventional X-rays. It is a very useful for diagnosing brain tumours.
MRI (magnetic resonance imaging) - uses magnetic and radio waves, meaning that there is no exposure to X-rays or any other damaging forms of radiation. This is a fairly new technique dating from the beginning of the 1980s which has recently become available for use with animals in a number of specialised units. MRI produces finely-detailed cross-sectional images of the body which yield far more information about the tissues than do other imaging techniques. MRI is one of the least invasive techniques and with CT scans it is invaluable for detecting brain tumours.
And most importantly - you. No-one else knows your cat like you do. You will be the first to notice if your cat is acting unusually or out of character. Cats are good at disguising pain and discomfort, which they perceive as weakness and therefore vulnerability, but it is much harder to disguise the signs from someone who knows the cat well. If you think something is wrong, get it checked. The annoyance and expense of calling on the vet may prevent or minimise major problems later on. And if a test proves your fears groundless, you will be able to sleep much better at nights.
Treatment
In most cases, the life of a cat suffering from cancer can be significantly prolonged by appropriate treatment. However, these treatments often come with side effects. It takes careful monitoring and assessment for these side effects to be avoided or at least minimised. But remember, the quality of life of your cat should should always come first. There may come a time when keeping a pet clingling to life does not justify the suffering it is going through. Your vet will know this, and will advise you of your options throughout the cat's treatment, and how to keep your cat's suffering to a minimum. It is therefore worthwhile talking things through with your vet before arriving at any decision.
There are three main ways to treat cancer in cats: surgery, radiation therapy and chemotherapy.
Surgery
Surgery is the oldest and most commonly used form of therapy and it is often the only option for most benign and some malignant cancers. Surgery may be recommended for several reasons. These include complete removal of a tumor, partial removal of a tumor, or exploration of a particular area to obtain a sample of tumor tissue and evaluate how far the cancer has spread through normal tissue. Generally, any tissue removed by surgery goes for a biopsy (i.e. it is given to a pathologist who will give a specific diagnosis based on what he finds).
The successful surgical removal of a tumour depands on many things, including the tumour's size and location, the type of tumour, and where and how extensively it has spread. Some cancers are too large or are in parts of the body where they cannot be removed completely by surgery alone. In these cases the surgeon will remove as much of the cancer as possible, while minimizing damage to surrounding normal tissues and vital structures. Because cancer cells have been left behind, additional treatment such as radiation or chemotherapy is used to attack the remaining cells.
Radiation therapy
Radiation therapy involves radiation at much higher doses than are used for diagnostic X-rays. The aim is to kill tumour cells with focused radiation. Focus is essential, because concentrated radiation does not just kill cancerous cells, but all cells that get in its way. Modern radiation treatment uses a number of techinques to make sure that the tumour receives the maximum radiation with minimal effect on the normal tissue nearby. Maximizing the effect on tumours is one reason that radiation treatments are given as a series of small doses rather than one large dose. Radiation is also used with good effect on localized tumours.
Radiation is used to clear cancer from parts which a surgeon cannot reach without killing his patient, and also on sites where a surgical operation is not practical in any case, for example with some tumours affecting the mouth, nose, or other head and neck sites including the brain. Sometimes the treatment will succeed in curing your cat. in other cases the tumour will be forced to shrink retreat, only regrowing after the cat has enjoyed cat many months, or even years, of good-quality life.
Chemotherapy (Anti-cancer drugs)
Certain types of cancer, particularly tumours of the lymph glands (lymphoma or lymphosarcoma, can be controlled well by anti-cancer drugs. Chemotherapy is also useful in fighting cancers with a high likelihood of spreading. Unfortunately anti-cancer drugs rarely cure animal tumours, but with some cancers they can produce remissions with an excellent quality of life for long periods.
The uncontrolled division of rogue cells within the body is what allows the tumours to grow and spread. Therefore most (but not all) chemotherapy drugs work by interfering with the ability of cells to divide. Side effects, when they occur, are often the result of the drugs affecting other cells in the body that need to divide rapidly, such as cells in the bone marrow, the intestinal tract and the skin. As a result side effects from chemotherapy most often include: a low white blood cell count, hair loss and gastrointestinal irritation.
The huge effort made to find treatment for cancers in humans has had the side-effect of an increasing number of effective drugs which can be adapted to the needs of feline patients. There is now a large number of different drugs for treating cancers in cats. The choice of which will be used for a particular cat's chemotherapy depends on the type of tumour being treated and how well the cat tolerates the treatment. Your vet will be able to discuss this with you and if necessary refer you to a specialist for further advice and/or treatment.
Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.
