Our veterinarians in Murfreesboro frequently encounter cats with lymphoma, a type of cancer that affects the white blood cells called lymphocytes. In this post, we will discuss the types of lymphoma affecting cats, how they are diagnosed, and the available treatment options.
What is lymphoma in cats?
This cancer affects the lymphocytes of a cat's immune system, which circulate through the blood and lymphatic vessels. It is linked with feline leukemia virus infection.
What are the most common symptoms of lymphoma in cats?
Lymphoma in cats can lead to a range of symptoms, depending on the location of the cancer. Intestinal lymphoma may cause diarrhea, vomiting, and weight loss, with large-cell lymphoma leading to a rapid onset of symptoms and small-cell lymphoma developing more slowly. Mediastinal lymphoma is found in a cat's chest and can cause breathing difficulties, often accompanied by fluid buildup around the tumor.
Renal lymphoma may lead to the accumulation of toxins in the blood, resulting in symptoms similar to kidney failure, such as reduced appetite, increased thirst, and vomiting. The central nervous system may also be affected in severe cases, causing behavioral changes, seizures, and difficulty walking.
What causes lymphoma in cats?
Cats are often affected by lymphoma due to the feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). However, the good news is that more and more cats are being vaccinated against feline leukemia as part of their regular vaccination and wellness care, which is reducing the incidence of feline leukemia and lymphoma. Nevertheless, there is still a lot of room for improvement, as lymphoma accounts for a significant portion of all cancers diagnosed in cats.
To prevent lymphoma in cats, it is advisable to avoid contact with FeLV or FIV-infected cats and stay away from smoky environments. Early detection of the disease can significantly increase the chances of survival for cats.
Where is lymphoma typically found in cats?
Lymphoma can develop in multiple organs since lymphocytes are found throughout your cat's body.
A cat can develop lymphoma in its nasal cavity, mediastinal, or gastrointestinal tract. The location and size of the lymphocytes determine how the lymphoma is classified.
- 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 nine years of age.
- Renal lymphoma is also associated with feline leukemia. This type of lymphoma impacts a cat's kidneys and may lead to kidney failure.
- 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 five years of age and is strongly associated with feline leukemia.
Stages of Feline Lymphoma
There are five stages of feline lymphoma (I to V). There are substages within each period where a cat either does or doesn't display signs of illness.
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 - 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 tissues (in addition to previously listed ones).
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 are treatment options for lymphoma in cats?
Chemotherapy is the primary treatment for cats diagnosed with lymphoma, although radiation can also be an option. If the lymphoma is confined to a single area, such as the cat's nasal area or abdomen, surgery (with or without chemo) may be recommended. If, for any reason, chemotherapy is not an option, prednisone may be prescribed as palliative or hospice care. You can discuss this with your veterinarian.
What is the prognosis for cats diagnosed with lymphoma?
With treatment, the prognosis for cats diagnosed with gastrointestinal large-cell lymphoma is about three to nine months. A small percentage of cats that reach full remission with treatment can live up to two years, although this is rare.
Cats diagnosed with small cell gastrointestinal lymphoma will require ongoing care with oral medications but could live two to three years with the disease for longer.
Sadly, cats diagnosed with mediastinal lymphoma and feline leukemia face a poor prognosis of about three 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 nine to twelve months.
Renal lymphoma, unfortunately, carries a very poor prognosis. The average survival rate for this type of lymphoma is only three to six months, though there are isolated reports of cats surviving far longer. Renal lymphoma tends 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 extend the cat's quality of life by a few weeks or 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.