Cancer


We frequently diagnose cancer in cats at our clinics. The most common types of cancer we see are lymphoma, squamous cell carcinoma, mammary tumours  and bone cancer.
Cancer is a broad description for any condition whereby certain body cells will divide abnormally to form lumps and growths. A cancer or tumour may be benign or malignant. A benign tumour will grow slowly and not spread to other parts of the body. These can easily be removed by a surgical procedure. Malignant tumours on the other hand are aggressive, fast growing and spread into the surrounding tissues and other parts of the body quite quickly. The prognosis for these tumours is poor and they may be controlled by surgery, chemotherapy and radiation therapy.

I strongly recommend you have your cat spayed at 6-8months of age. This will significantly reduce the chance of malignant breast cancer.

Lymphoma is the most common malignant cancer we see and I will spend some time discussing this as we can, with chemotherapy, improve your cats quality of life for quite a while.

Lymphoma:

Lymphocytes are white cells that are found all over the body and especially concentrated in lymph nodes and also the liver, kidney, spleen and bone marrow. Lymphoma results when these cells start to divide uncontrollably and we will classify the tumour according to its location. For example mediastinal or gastrointestinal lymphoma.
In younger cats this may be caused by feline leukemia virus, however this is quite rare now in HK.
We now see this tumour quite commonly in middle age to older cats.

Diagnosis:
you may notice that your cat has been losing weight, vomiting, poor appetite, breathing with difficulty or just listless. Sometimes you will see no symptoms and on your annual visit to the vet clinic for a check up, we will feel an abnormal lump in the abdomen.
We may request X-rays, ultrasound, blood test or even an exploratory laporotomy(open the abdomen surgically) to look for the lump. We may take a biopsy and a needle aspirate to evaluate the cells under the microscope. These cells can also be typed by a histopathologist as B or T cells which will also give us an indication of the prognosis.

Treatment:
Lymphoma is a type of tumour that in some cases can respond very well to chemotherapy. Some people worry about chemotherapy and the side effects that it may cause. However the aim of chemotherapy in animals is to maintain the best quality of life with minimal side effects.

There are possible side effects, so close monitoring is essential and prompt action required if any side effects are seen. However, provided that these precautions are taken, most cats tolerate these drugs very well with very minimal side effects.
We will decide on a specific protocol for your cat. Usually there will be two phases of therapy. First the induction phase whereby your cat will need weekly intravenous drugs for about two months. After that we will continue a protocol of maintenance every three weeks. This maintenance protocol generally will continue for the rest of his life. The drugs we commonly use are vincristine, cyclophosphmide and prednisilone. These drugs will suppress the bodies bone marrow and we will do a regular blood test to make sure the healthy blood cells remain within normal levels.

Prognosis:
without chemotherapy, the prognosis is poor and your cat will usually die within a month. With chemotherapy your cats quality of life will be significantly improved and the length of life extended. Depending on the aggressiveness of the tumour, remission may last for up to a year or more. Some tumours are so aggressive they do not respond to the therapy. We will see a response to treatment within two weeks. The tumour will become smaller and your cat will appear much happier.
Some people do not wish for there cats to get chemotherapy. I strongly recommend that you try for at least a couple of weeks and see how your cat responds before quitting.