Our Toledo vets often see cats with lymphoma. This type of cancer affects specific white blood cells in the cat's body called lymphocytes. In this post, we list the types of lymphoma seen in cats, how they are diagnosed and how they are treated.
What is lymphoma in cats?
This systemic cancer impacts the lymphocytes of a cat's immune system. Lymphocytes make their way through your cat's body in the blood and lymphatic vessels. The condition is associated with the viral infection feline leukemia.
What causes lymphoma in cats?
The felime leukemia virus (FeLV) and feline immunodeficiency virus (FIV) often cause lymphoma in cats. More cats are being immunized against feline leukemia as part of their annual wellness and vaccination care, which is leading to decreasing rates of feline leukemia and lymphoma. That said, there is still much room for improvement. Lymphoma makes up about 30% of all cancers diagnosed in cats.
Avoiding contact with FeLV or FIV-infected cats and areas with smoke can also help prevent lymphoma in cats. Early detection of the disease can improve a cat's chances of survival.
Where is lymphoma typically found in cats?
Lymphoma can develop in multiple organs since lymphocytes are found throughout your cat's body.
A cat's nasal cavity, mediastinal or gastrointestinal tract are common locations for the disease. The location of the disease and the size of the lymphocytes (either small cell or large cell) will determine how your cat's lymphoma is classified.
- Renal lymphoma is also associated with feline leukemia. This type of lymphoma impacts a cat's kidneys and may lead to kidney failure.
- Intestinal lymphoma is the most common form of lymphoma in cats. Found in the GI tract, this cancer is most often seen in cats over 9 years of age.
- Mediastinal lymphoma affects the lymphoid organs found in a cat's chest. These organs include the lymph nodes and the thymus. This type of lymphoma is typically found in cats around 5 years of age and is strongly associated with feline leukemia.
What are the most common symptoms of lymphoma in cats?
When it comes to lymphoma in cats, symptoms will depend on where the cancer is located.
Diarrhea, vomiting and weight loss are common in cats with intestinal lymphoma. These symptoms will occur very rapidly — often in just a matter of days or weeks — in cats with large-cell intestinal lymphoma. Cats with small-cell intestinal lymphoma will experience a much slower onset of symptoms.
Mediastinal lymphoma is found in a cat's chest area, which commonly leads to breathing challenges. In some cases, fluid may accumulate around the tumor, making it increasingly difficult for the cat to breathe.
In cats with renal lymphoma, toxins build up in their blood system, often causing them to show common symptoms related to kidney failure. These may included reduced appetite, increased thirst and vomiting. In some circumstances, the cat's central nervous system may be impacted, in which case symptoms such as instability while walking, behavior changes and seizures may occur.
Feline Lymphoma Stages
There are five stages of feline lymphoma (I to V). There are substages within each period where a cat either does or doesn't show symptoms of sickness.
Stage 1 - Cancer cells are only present in a single lymph node.
Stage 2 - Cancer cells start to appear in more than one lymph node, but the cancer remains within the same area of the body.
Stage 3 - Cancer cells develop in lymph nodes throughout the body.
Stages 4 & 5 - The cancer cells affect specific body parts. In Stage 5, cancer cells appear in the spleen and/or liver. In the final stage, cancer cells reach the bone marrow and/or other tissue (in addition to the ones previously listed).
How is lymphoma in cats 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
Can lymphoma be misdiagnosed in cats?
Yes, it's possible for lymphoma to be misdiagnosed in cats. Since lymphoma can be difficult to diagnose without further testing and many other conditions can cause similar symptoms, it's not uncommon for cats to become ill without receiving a definitive diagnosis of lymphoma. The diagnostic tests and tools mentioned above are often required to diagnose the disease.
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.
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.
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.