Lymphoma in Cats: Types, Signs, Diagnosis and Treatment Options

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

Hearing the word lymphoma about your cat is frightening. It is one of the most common cancers in cats, and also one that often responds to treatment. Understanding the types and options helps you make informed decisions with your vet.

What is lymphoma?

Lymphocytes are white blood cells that fight infection. In lymphoma, they multiply out of control, forming tumors, or infiltrating organs. Because lymphocytes travel through the body, lymphoma can appear almost anywhere, though some sites are more common than others. See cancer in cats.

Types by location

• Gastrointestinal (alimentary). The most common form in cats today, affecting the stomach, small intestine or colon. It can be low-grade, slow-growing, or high-grade, which is aggressive.
• Mediastinal. In the chest, near the thymus, sometimes causing fluid in the chest and breathing difficulty. Often linked with FeLV.
• Multicentric. Affecting several lymph nodes.
• Renal. In the kidneys.
• Nasal. In the nose and sinuses.
• Other sites, such as the skin, eyes, spine or brain.

Causes and risk factors

• FeLV infection. The virus greatly raises the risk. See FeLV and FIV in cats.
• FIV infection.
• Chronic inflammation, for instance in the gut. Some researchers link inflammatory bowel disease with intestinal lymphoma. See inflammatory bowel disease in cats.
• Tobacco smoke exposure.
• Age. Most cats are middle-aged or older, though FeLV-related lymphoma affects younger cats.
• Genetics, where Siamese cats appear at higher risk.

Signs

Signs depend on the site:

• Gut: weight loss, vomiting, diarrhea, poor appetite, lethargy. See cat vomiting causes.
• Chest: rapid or labored breathing, open-mouth breathing, cough. See cat panting and open-mouth breathing.
• Lymph nodes: swollen lumps under the jaw, in front of the shoulders or behind the knees.
• Kidneys: increased thirst, weight loss, kidney failure signs.
• Nose: sneezing, nasal discharge, facial swelling.
• General: fever, lethargy, reduced appetite, weight loss.

Diagnosis

The vet may suggest bloodwork, FeLV and FIV testing, X-rays and ultrasound, then collect a sample of the abnormal tissue. A fine needle aspirate may be enough for swollen lymph nodes. Intestinal disease often needs biopsies, by endoscopy or surgery, to tell lymphoma from inflammatory bowel disease. Special tests of the cells help identify the type and grade.

Treatment

• Chemotherapy. The main treatment. Low-grade intestinal lymphoma is often treated with oral medication, usually chlorambucil and prednisolone, which can give long remissions, sometimes more than two years. High-grade lymphoma needs combination chemotherapy, often given by injection and tablets at an oncology clinic, with a high chance of remission, though shorter than in low-grade cases.
• Radiation therapy, for localized disease such as nasal lymphoma.
• Surgery, in selected cases.
• Supportive care, such as anti-nausea drugs, appetite stimulants, fluids, pain relief and nutrition. See cat not eating: causes.

Is chemotherapy hard on cats?

Cats generally tolerate chemotherapy better than people, with lower doses and fewer side effects. Some may have a poor appetite, vomiting or diarrhea. Hair loss is rare, though whiskers may fall out. Your vet will monitor blood counts.

Outlook

Outcomes vary widely. Cats with low-grade intestinal lymphoma often live well for one to three years or more. Aggressive forms may respond to treatment but relapse sooner. FeLV-positive cats generally have shorter survival. Without treatment, survival may be weeks to months.

Quality of life

Talk with your vet about goals, costs and quality of life. Treatment aims to keep your cat comfortable and eating, and many cats enjoy good time. See cat quality of life and saying goodbye and cat pet insurance guide.

Prevention

• Test new cats for FeLV, and vaccinate at-risk cats. See cat vaccination schedule.
• Keep cats indoors.
• Avoid smoke exposure.
• Have regular checkups, especially for older cats.

Making decisions with your vet

After a diagnosis, ask what type and grade of lymphoma your cat has, what the treatment options are, what the likely outcomes are and what the costs and time commitments will be. Ask about the side effects, and what you will need to do at home. A referral to a veterinary oncologist can give you a fuller picture, though many general vets also treat low-grade lymphoma with oral medication.

Giving oral chemotherapy safely

Chlorambucil and similar drugs should be handled with gloves, and kept away from children and pregnant women. Do not crush tablets. Wash hands after handling, and wear gloves when cleaning litter, since small amounts of drug may be in urine and feces. Your vet will explain safe handling and disposal. See how to give a cat a pill.

Supporting your cat during treatment

Offer tempting food in small portions, and keep fresh water available. Keep a record of appetite, weight, vomiting and stool. Attend blood tests on schedule, since chemotherapy can lower blood counts. Provide comfort, warmth and company. Many cats continue to enjoy normal life through treatment.

Emotional support

A cancer diagnosis is hard on families. Talk to your vet about what to expect, and lean on friends or support groups. Many owners find comfort in knowing they made the best choice they could for their cat.

When to see a vet

See a vet if your cat has lumps, weight loss, vomiting or breathing trouble. Use the US vet directory to find a clinic.

This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.