Lymphoma in cats is the most common cancer in felines. The disease is most often found in the intestines, as vaccination against the feline leukemia virus (FeLV) and testing for the feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) have reduced lymphomas in the chest, spleen, bone marrow, thymus, and lymph nodes.
Early diagnosis and treatment may help your cat live comfortably for years.
Lymphoma in Cats Symptoms
The symptoms of lymphoma in cats depend on where the cancer is growing. Lymphoma in the lymph nodes comes as swellings around the neck, shoulder blades, and knees. Lymphoma of the chest (mediastinal lymphoma) causes respiratory symptoms. If your cat has neurological symptoms (nervous system involvement), you may notice changes in behavior, difficulty in walking, and fits.
Regardless of the site, some symptoms are common to all lymphomas:
While older cats are most often affected, lymphoma can happen at any age.
Intestinal Lymphoma in Cats
Lymphoma in cats is now most commonly seen in the intestines. Intestinal lymphomas usually cause poor eating, weight loss, diarrhea, and vomiting. The blood tests are often normal, but ultrasound of the abdomen may show thickened intestines, enlarged abdominal lymph nodes, and tumors. Since these findings are common to inflammatory bowel disease, vets usually require a biopsy for a lymphoma diagnosis.
Intestinal lymphomas can be large cell and small cell lymphomas. Large cell lymphomas are aggressive — they quickly grow and are invasive. Chances for survival are lower with these lymphomas.
A small cell lymphoma in cats is slow-growing. Since it is not aggressive, cats have higher chances of survival.
Stages of Cat Lymphoma
Cancer staging helps vets choose the best treatment for lymphoma in cats. The feline lymphoma stages predict the behavior of the cancer and survival odds. The higher the number of stages, the more cancer has spread. Staging tests depend on the lymphoma type and often include radiographs (X-rays), CT scans, or biopsy.
Your vet will choose the treatment based on the type and grade of your cat’s lymphoma. Microscopy divides lymphomas in cats into the large cell and small cell lymphomas.
Cat lymphomas are also divided based on location — nasal cavity, mediastinal, multicentric, gastrointestinal, and others. Each cancer can have a low, intermediate, and high grade depending on the cell division.
Lymphoma in Cats Treatment
The treatment of lymphoma in cats is usually through chemotherapy. Your oncologist may prescribe a combination of drugs based on the location and grade of the lymphoma. These drugs are given orally or by intravenous injection once a week for a month or longer.
A large mass in the abdomen may need to be removed by surgery. Nose lymphomas respond well to radiation. If a cat is not responding to treatments, vets give a steroid (prednisolone) as palliative therapy. This allows for a temporary remission of 2 to 4 months, improving the quality of life during the last stage of a cat’s life.
Cats with lymphoma of the chest, widespread lymphoma, lymph node lymphoma, and large cell intestinal lymphoma will probably receive chemotherapy with a combination of three or four drugs. Almost half of the cats with lymphoma live for a year with such treatment. Two-year survival may be at 40%.
Small cell lymphomas, which are not considered aggressive, can be treated at home. A steroid-based drug such as prednisolone and a chemotherapy drug your cat can take by mouth (like chlorambucil) are used for treatment. Cats usually tolerate these treatments well. Medication may help your cat survive for 2 to 4 years.
Lymphoma in Cats Prevention
Viruses FeLV and FIV often cause lymphoma in cats. Vaccination against FeLV and testing for both these viruses help with disease prevention and spread. Avoiding contact with FeLV or FIV-infected cats and areas with smoke can also prevent lymphoma in cats. Early detection of the disease can improve the chances of survival.