Lymphoma in Dogs and Cats

Lymphoma (or Lymphosarcoma) is a common type of cancer encountered in small animal practice. Although life-threatening, one positive thing is that it is very rewarding to treat. It may be caused by viruses such as Feline Leukaemia Virus (which we routinely vaccinate against) but often the underlying cause is not known.

Lymphoma is a cancer of the lymphocytes, a type of white cell commonly found in the lymph nodes and bone marrow. It is often very widespread in the body and will grow quickly. That aggressive growth will cause a rapid progression of illness but makes it very susceptible to treatment.

One of the key signs I often see will be swelling of one, several or all of the lymph nodes. These glands can be found in the neck, legs and under the jaw and also in the abdomen or even chest. They can be felt and often seen using ultrasound. A fine needle aspirate usually obtains many cells which can be stained on a slide and identified using a microscope. Blood tests are done to assess the general level of health, kidney and liver function and count the circulating red and white cells.

lymphoma cells in a RBC background from a bone marrow biopsy.


The decision to treat this condition is never easy to make. In part it is because we are using drugs and in people chemotherapy is considered to be a very unpleasant thing to undergo. An animals welfare is always the priority and although a course of treatment may not be without side-effects, these are usually minimal and easily treated. The strength of drugs used is much less than in people and we always have the option to reduce doses or stop treatment at any point. Success rates are 70-80% of which a number will go into complete long-term remission.

I have treated many animals with lymphoma and in all cases, I have looked after, I have been really pleased to make a difference and to try to give a longer and better life to the pet. I rarely see significant side effects and very often within one week of starting treatment a marked improvement can be seen. Treatment courses will use a number of different drugs given at certain intervals over, a six month period of time with periodic monitoring of blood samples, which we can do in the clinic, to ensure everything is going to plan.

This is just a brief overview about the disease and the treatment. However if you want more information, please feel free to contact me at the clinic. Best wishes Ian