Lymphoma is one of the most common forms of cancer in cats, accounting for around 1/3 of all tumours. Lymphoma is one of the most common forms of cancer in cats, accounting for around 1/3 of all tumours. The tumour cells originate and proliferate from both B and T lymphocytes in the bone marrow, lymph nodes and visceral organs. As a result, lymphoma can appear almost anywhere affecting vital organs such as the liver, kidneys and gastro-intestinal tract.
Posted: 02 May 2019
– this form of lymphoma affects the gastrointestinal tract, abdomen, liver and surrounding lymph nodes. It’s the most common form of feline lymphoma but is also the least likely to be associated with the Feline Leukaemia Virus (FeLV). Signs to look for include;
– this form of feline lymphoma is closely associated with FeLV. It generally involves multiple lymph nodes and organs. Unfortunately, the prognosis is poor if the cat is FeLV positive. Look for;
– this form of lymphoma affects the thymus and associated lymph nodes. Like the multicentric form, it can also be linked to FeLV. Typically, there will be a mass in the pleural cavity. Signs include;
- this is the most common renal tumour in cats and often presents with sudden onset renal failure. A clinical examination will show;
– this can be both unilateral or bilateral and can precede the onset of systemic lymphoma. All parts of the eye and retrobulbar space can be affected, with the uvea being the most commonly affected site. Signs may include;
Lymphoma can also be categorised according to the type of neoplastic lymphocyte cells. Broadly speaking they are divided into two main types;
These two types of lymphoma vary in behaviour, so it’s important to make a precise and definitive diagnosis to allow you to make the right choice of treatment. The grade of tumour will also affect the prognosis.
This is best achieved using a combination of blood tests and imaging procedures.
Routine blood tests would include haematology (red and white cell counts), biochemistry and electrolytes. Urinalysis is also of value. Look for;
Other investigations would include biopsy, radiography, ultrasound and CT. Fine needle aspirates or biopsies are often absolute and diagnostic.
Chemotherapy – this is often the treatment of choice, frequently given in combination with surgery or radiotherapy. There will be some cases which are amenable to surgery, where a mass can be resected (for example an obstructing mass in the small intestine) and removed prior to starting chemotherapy.
Some of the drugs used include;
The aim of chemotherapy is to induce remission by destroying most of the cancer cells. This is achievable in 50-75% of cats. Even those cats that don’t go into remission will often feel better for a reasonable period of time. The average survival for cats in remission is between 6 and 9 months, though in a small number of cases they may be in complete remission for more than 2 years. The length of remission will depend on several factors, such as;
Eventually, the animal will come out of remission as the cancer cells return. At this stage, the chemotherapy protocol is often changed to introduce new drugs, but in time the animal will no longer respond to therapy.
These are frequently found in the gastrointestinal form of lymphoma. They tend to be slow growing and may require surgery if causing an obstruction. Chemotherapy is often used, and in these cases we tend to use chlorambucil and prednisolone.
Most cats will show a good response to to treatment (85-90%) within just a few weeks. The survival times of cats that are treated with low grade lymphoma is between 1 and 2 years.
Before embarking on any chemotherapy for lymphoma, it’s essential you discuss all aspects of the medication (especially the side effects) and likely outcome with the owner. It’s so important to remind them that;