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Understanding Lymphoma in Cats

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As a pet parent, a cancer diagnosis is one of the worst fates you can imagine for your fluffy ball of joy. Unfortunately, for some, cancer will become a part of the conversation when it comes to your kitty.

Lymphoma is the most frequently diagnosed of all cancers in cats. It makes up 90 percent of feline blood cancers and 33 percent of all tumors in cats. But what exactly is lymphoma, and what causes it? More importantly, how can you help your furry friend if they develop lymphoma?

What Is Lymphoma?

Lymphoma is cancer of the lymphatic system. More specifically, it’s an abnormal, malignant growth of the lymphocytes, a type of white blood cell that plays a big part in your kitty’s immune system. Lymphoma can affect the entire lymphatic system or just portions of it. Cats are unique in that feline lymphoma often starts in atypical locations, such as in their nasal passages, spinal cord, kidneys, or eyes. For most species, including humans and dogs, lymphoma originates most often in the lymph nodes.

Cats of any breed and any age can get lymphoma, but it’s most common in cats who are 10-12 years old. In young cats, lymphoma usually originates in the chest cavity; whereas, senior cats often develop the condition in their intestinal tract.

How the Lymphatic System Works

Understanding the lymphatic system might help you understand lymphoma in cats. Basically, the lymphatic system is a network that carries lymph fluids throughout your cat’s body. These fluids deliver oxygen and nutrients to other cells, absorb fat, and remove the bad stuff (like bacteria, viruses, and waste). For this reason, lymphoma is classified as systemic, meaning the cancer travels throughout the entire body – even if it’s not metastasizing in the traditional sense. What does that mean for your li’l pal? Surgically removing a tumor won’t necessarily remove the lymphoma. It’s important that you discuss realistic treatment options with your veterinarian.

What Causes Lymphoma in Cats?

The exact cause is unknown. However, exposure to the feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) can greatly increase your kitty’s risk for developing lymphoma. Our strategic partner the American Society for the Prevention of Cruelty to Animals® (ASPCA®) always recommends an indoor-only environment for your feline friend, and this is just one more reason to stay up-to-date on vaccinations and keep your kitty inside. There has also been some research linking secondhand tobacco smoke to lymphoma in cats.

black and white cat with green eyes and pink nose

Symptoms and Types

Because lymphoma can originate in different areas of the body, symptoms can vary. Almost all kitties with lymphoma experience diminished appetite and weight loss. Additional symptoms relate to the type of lymphoma and the affected area:


Multicentric lymphoma is the type that probably comes to mind when you hear the word lymphoma. Originating in the lymph nodes, it’s often accompanied by swollen lymph nodes and depression. If you have concerns, carefully check your kitty’s jaw, under arms, and groin areas for swollen lymph nodes.


This form affects the gastrointestinal tract, abdomen, and liver. It's currently the most common type since FeVL vaccinations have greatly reduced other forms of lymphoma in cats. Symptoms include:

  • Lethargy
  • Vomiting
  • Constipation
  • Diarrhea
  • Black or tarry stool
  • Blood in stool


Originating between the pleural sacs and lungs, mediastinal lymphoma is also associated with:

  • Open-mouth breathing
  • Persistent cough


Renal lymphoma starts in the kidneys. Look for symptoms like:

  • Vomiting
  • Weakness
  • Increased urination and thirst

grey british shorthair cat with yellow eyes

How to Diagnose Lymphoma in Cats

To diagnose lymphoma, your veterinarian will need to take a detailed medical history and complete a series of tests. A bone marrow biopsy can confirm the diagnosis conclusively, but your furry friend may first undergo a blood test, biochemistry profile, urinalysis, and X-rays. If your veterinarian suspects the liver or spleen is affected, your kitty may need an ultrasound. Many cats are also tested for FeVL at this time. Identifying the origin and stage of your cat’s lymphoma is essential to developing the best treatment plan so that you may be referred to a veterinary oncologist.

Prognosis, Treatment, and Prevention

As with human forms of cancer, there is currently no cure for lymphoma in cats. The general prognosis is 6-9 months. However, in reality, most individual cats do much better or much worse – it all depends on the type and stage of lymphoma and your cat’s general well-being. In fact, young cats who test negative for FeVL can go into long-term remission and lead very full lives. In all cases, treatment centers on quality of life and how you can make your cat as comfortable as possible for the longest amount of time.

Treatment Options for Cats with Lymphoma

In some cases, radiation or surgery can be effective. However, the most common treatment is chemotherapy. This involves a mix of different chemo drugs that your veterinarian will need to monitor and adjust. You should pay close attention your cat’s food and water intake and be in regular contact with your veterinarian so you can discuss any complications. Cats tolerate chemotherapy fairly well (without as many negative side effects as people tend to experience), and it can be very fast-acting in terms of symptom relief.

Your kitty’s initial chemotherapy protocol will likely last 26 weeks, so it’s critical that you are honest with your family’s capacity to handle this type of treatment – in terms of time, expense, and emotional impact. If you decide not to go forward with chemotherapy or other treatments, steroids can help manage your cat’s symptoms. Your veterinarian may also prescribe pain medications, but make sure everyone in your household is familiar with your pal’s medication schedule. It’s easy to cause an accidental overdose with powerful pain medications.

How to Prevent Lymphoma in Cats

In terms of prevention, the most important thing you can do is to make sure your kitty gets the FeVL vaccination. Avoid exposure to cats with FeVL or FIV, and don’t smoke around your feline friend. Additionally, if your cat is 7 years or older, speak with your veterinarian about getting a twice-yearly workup that includes blood chemistry testing. This could help catch the disease earlier and improve your pal’s quality of life.

Pet health insurance may help to cover the cost of the critical care your kitty needs

How Pet Health Insurance Can Help

When you’re dealing with a cancer diagnosis for your loved one, the last thing you need to worry about is the cost of treatment. Pet health insurance may help to cover the cost of the critical care your kitty needs. Is your cat covered? Get a quote today.

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