Lymphoma in Cats
Lymphoma, also called lymphosarcoma or LSA, is a cancer of special cells called lymphocytes. Lymphoma is the most common cancer affecting cats and can occur in nearly any part of the body. Early detection and intervention can be key to improving your cat’s quality of life. Continue reading to learn more about lymphoma and how it’s diagnosed and treated in cats.
What is lymphoma?
Lymphoma or lymphosarcoma (LSA) is a cancer of the cells of the immune system called lymphocytes. Lymphocytes are present throughout the body, so cats can develop lymphoma in multiple organs. Lymphoma is classified by the location of the disease (e.g. gastrointestinal tract, kidney, mediastinal) and the size of the lymphocytes (large cell versus small cell). Lymphoma is the most common malignancy of cats, accounting for as much as 30 percent of all feline cancers.
Who’s at risk?
Cats of any age can get lymphoma, although most affected animals are 10 to 12 years of age. Unvaccinated outdoor cats are at greater risk than indoor cats due to their greater exposure to feline leukemia (FeLV) infection. And recent studies have indicated that cats routinely exposed to tobacco smoke are at elevated risk for gastrointestinal lymphoma.
Signs of Lymphoma in Cats
Cats with lymphoma present with a variety of signs because lymphocytes can be found in nearly every organ in the body. Most species including man present with large lymph nodes, but this is a rare form of LSA in cats. Young cats typically present for masses in the chest cavity and owners notice signs of difficulty breathing. Older cats develop the tumor in their intestines quite commonly and owners may notice signs such as weight loss, decreased appetite, diarrhea, or vomiting.
Cats can also develop LSA in areas as diverse as the nasal passages, kidneys, spinal cord, liver, eyes, or a single lymph node, and the signs seen will be more specific for the organ affected.
Diagnosis and Clinical Staging of Lymphoma in Cats
Because of the organs that LSA commonly involves, staging a cat with LSA can involve aspiration (collecting cells) of one or more lymph nodes or masses, thoracic (chest) radiographs, abdominal radiographs, or ultrasound (to look for big lymph nodes in the abdomen and to look at the liver and spleen), or bone marrow examination.
Obtaining blood for a complete blood count and biochemical profile, testing for feline AIDs (FIV) and leukemia (FeLV), and a urinalysis is always advised. These tests can help assess your cat’s overall health and provide information that potentially influences treatment recommendations.
Sometimes, special stains to determine if the LSA is of B-cell or T-cell origin (B-cells and T-cells are specific types of lymphocytes) are recommended because of prognostic significance, although treatment recommendations may be the same for either type. Staging the disease can be critical in choosing treatment protocols for your cat.
Treatment Options and Prognosis for Cats with Lymphoma
Lymphoma can be treated with chemotherapy, surgery, radiation therapy, or combinations of these modalities. Prognosis is influenced by lymphoma subtype and anatomical location. Depending on the site of the tumor, mean survival times with chemotherapy range from 6-9 months. The problem is that this is only an average and most cats tend to do either much worse or much better.
For example, with treatment, approximately 70% of cats with low-grade lymphoma will go into remission. Lymphoma is never truly “cured,” but remission is a term that is used to describe the temporary resolution of all signs of lymphoma. The average remission for low-grade lymphoma is 2-3 years, meaning 2-3 years without any signs of disease.
Whereas high-grade gastrointestinal lymphoma does not respond as well to treatment. Only 25-50% of cats with high-grade lymphoma achieve remission with treatment. Typically, this period of remission lasts only 2-9 months, and then cats become ill again.
How can I reduce the likelihood of my cat developing lymphoma?
While lymphoma cannot be prevented, the chances that a cat will develop the disease may be reduced through vaccination against FeLV, by preventing contact with FIV or FeLV infected cats, and by making sure your cat doesn’t live in an environment contaminated by tobacco smoke.
Since early detection of the disease may improve an animal’s chances for survival, it’s recommended that all cats seven years of age and older undergo annual physical exams that include thorough palpation of the patient’s body and possible blood testing.
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