What causes lymphoma in cats?
Lymphoma is a systemic cancer that affects the lymphocytes of the cat's immune system. Lymphocytes travel through your cat's body in the blood and lymphatic vessels. This condition is associated with the viral infection feline leukemia.
Thanks to increasing numbers of cats being immunized against feline leukemia as part of the annual wellness and vaccination care, both feline leukemia and lymphoma are becoming less common than they once were, although there is still much room for improvement. Lymphoma makes up approximately 30% of all cancers diagnosed in cats.
What are the different types of lymphoma that can affect cats?
Lymphocytes are found throughout your cat's body, which means that lymphoma could develop in multiple organs.
Common locations of the disease include the cat's nasal cavity, gastrointestinal tract or mediastinal. Your cat's lymphoma will be classified based on the location of the disease and the size of the lymphocytes (either small cell or large cell).
- Intestinal lymphoma is the most common form of lymphoma in cats. This cancer is found in the GI tract and is most often seen in cats over 9 years of age.
- Mediastinal lymphoma affects the lymphoid organs found within the cat's chest. These organs include the lymph nodes and the thymus. Strongly associated with feline leukemia, this form of lymphoma is typically seen in cats around 5 years of age.
- Renal lymphoma is also associated with feline leukemia. Renal lymphoma affects the cat's kidneys and may result in kidney failure.
What are the signs that my cat might have lymphoma
Lymphoma in cats symptoms depend upon where the cancer is located.
- A cat with intestinal lymphoma will often experience diarrhea, weight loss and vomiting. In cats with large cell intestinal lymphoma, these symptoms can come on very rapidly, in a matter of just days or weeks, whereas cats with the small cell version of the disease will show a much slower onset of symptoms.
- Because mediastinal lymphoma is found in the cat's chest area breathing difficulties are a common symptom of the disease. In some cases, fluid can build up around the tumor making it increasingly difficult for the cat to breathe
- As toxins build up in the blood system, cats with renal lymphoma will show common symptoms related to kidney failure including vomiting, reduced appetite, and increased thirst. In some cases the cat's central nervous system may be affected, in which case symptoms such as seizures, instability while walking and behavior changes may occur.
How is feline lymphoma diagnosed?
Depending on the extent of the disease and the location, either fine needle aspiration cytology or a biopsy will typically be used to diagnose lymphoma in cats.
In some cases, vets may require sampling of bone marrow or other organs, or molecular testing on tissues or blood in order to provide a definitive diagnosis of lymphoma.
Diagnostics may also include:
- Bloodwork such as CBC (Complete Blood Count) and full chemistry panel
- Testing for feline leukemia FeLV/FIV
- Urinalysis
- Ultrasound imaging to evaluate the cat's GI tract, spleen, liver and lymph nodes
- X-rays to evaluate lungs and lymph nodes
What is the treatment for lymphoma in cats?
Chemotherapy is the primary treatment used for cats diagnosed with lymphoma although radiation can also be an option and surgery (with or without chemo) may be recommended if the lymphoma is confined to a single area such as the cat's nasal area or abdomen.
Your veterinarian or veterinary oncologist will be able to recommend the best treatment for your pet based on their specific condition.
If for any reason chemotherapy is not an option prednisone may be prescribed as palliative or hospice care.
What is the prognosis for cats diagnosed with lymphoma?
With treatment, the prognosis for cats diagnosed with gastrointestinal large cell lymphoma is about 6 - 9 months. A small percentage of cats that reach full remission with treatment can live up to 2 years, although this is rare.
Cats diagnosed with small cell gastrointestinal lymphoma will require ongoing care with oral medications but could live 2 - 3 years with the disease of longer.
Sadly, cats diagnosed with mediastinal lymphoma and feline leukemia face a poor prognosis of about 3 months.
Cats that do not have feline leukemia, who are diagnosed with mediastinal lymphoma, may show a full or partial response to chemotherapy. These cats have an average survival time of about 9-12 months.
Renal lymphoma, unfortunately, carries a very poor prognosis. Average survival with this type of lymphoma is only 3-6 months, though there are isolated reports of cats surviving far longer. Renal lymphoma has a tendency to spread to the brain and central nervous system; this occurs in approximately 40% of renal lymphoma cases and worsens the prognosis for this disease.
If not treated with chemotherapy, large cell lymphoma in cats will progress very quickly and soon be fatal. Palliative treatments may help to extend the cat's quality of life by a few weeks or possibly months.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.