Cancer is not one condition, but a term that is used to describe any form of malignant growth. A cancerous growth may have a tendency to invade surrounding tissues and recur locally if removed, or it may be likely to spread to other parts of the body very early in its development, forming secondary tumors in sites around the body, called metastases.

Signs Your Cat Has Cancer

Whereas benign tumors generally only grow slow, and tend to not invade the tissues around them and don’t spread to other parts of the body, malignant tumors invade and destroy the tissue in which they originate and are likely to spread both to nearby tissues and to other parts of their body, causing a general loss of condition as well as signs relating specifically to the organs affected. The division b etween benign and malignant growths is not always clear-cut, with some cancers being highly malignant, and other being much less likely to invade other tissues in the body. They will generally cause a swelling of the body tissue involved, and may also cau se problems due to the production of other substances such as fluid that builds up within the chest or abdomen, or hormones in the case of tumors of the glandular tissue.


The cause of many cancers in unknown, but some can be triggered by repeated irritation from a carcinogen, or cancer-promoting agent. For example, in female cats it is known that long-term treatment with drugs that mimic the effect of the female hormone progesterone can increase the chances of breast tumors developing, and repeated sunburn of the ear of white cats can result in a type of tumor known as a squamous cell carcinoma developing on the ear tips. There is some evidence to suggest that a particular type of growth, know as fibrosarcoma, can develop at the site of vaccination in the scruff of the neck, although it is estimated that only one in 10,000 vaccinated cats develops this problem.

By far the most common cause of cancer in cats is infection with feline, which can cause a cancer o f the white blood cells known as lymphosarcoma to develop. This may manifest itself within the blood but, more frequently, it causes tumors to develop around the body, and particularly within the lymph nodes, such as those found adjacent to the intestines . In young cats, lymphosarcoma most commonly develops in the thymus gland.


The diagnosis of cancer is not always straightforward. An obvious mass on the body can be removed and sent off to a laboratory for analysis, or if complete removal is not feasible, a biopsy specimen can be taken. Sometimes, sufficient material for diagnosis can be obtained by a needle biopsy, a minor procedure where a needle is pushed into the mass and used to suck back come cells. A cat with a malignancy will usually be eating more than normal, yet losing weight and body condition. Specific signs of illness will relate to the organs affected by the growth – for example, a cat with tumors in its kidneys will eventually show the signs normally associated with kidney failure, such as bad breath, inappetance and excessive thirst.

Cancer is no longer necessarily a death sentence for a cat but early diagnosis is vital to improve the chances of successful treatment, so it is essential that the cat receives prompt veterinary atten tion. The idea form of treatment for any cancerous growth is complete surgical removal, and this is often possible, although the cancer may already have spread without this being obvious at the time of surgery. Surgery may be very straightforward id the tumor is situated superficially in an area with plenty of loose skin, but may require major reconstruction if it is in a more inaccessible site such as within the bone of the jaw.

Some tumors may not lend themselves to surgery, and especially in the case of lymphosarcoma, very effective chemotherapy regimes have been devised to control the problem. Anti-cancer drugs are not generally used in as high does as they are in humans, and the aim of treatment is usually to control the cancer and give the cat an extra lease of life, without most of the troublesome side-effects that can be associated with more aggressive chemotherapy. The most advanced form of cancer treatment for animals is radiotherapy, sometimes coupled with surgery. This is only available in a few referral centers around the country, and has to be administered on a regular basis under deep sedation or general anesthesia to prevent the animal from moving around during the procedure.

Even with the most up-to-date treatments. There are still some cancers that are not amenable to treatment, and in these cases the veterinary surgeon has to work together with the owner to ensure the cat is kept comfortable and contented until the time that euthanasia becomes the kindest option.