Lymphoma is a type of blood cancer that affects the lymphocyte cells, a type of white blood cell that is an essential component of the body’s defenses in the immune system. Lymphoma in cats is responsible for 90 percent of blood cancers and 33 percent of all tumors. Cats suffer from lymphoma more than any other animal. It is also the most common cause of hypercalcemia in cats, a condition where the calcium levels in the blood are above normal and can cause weak bones, kidney problems and more.
Cats that are infected with the feline leukemia virus (FeLV) are 60 times more likely to develop lymphoma than cats who do not have the virus in their system. Cats that have been infected with the feline immunodeficiency virus (FIV) are also at risk for developing lymphoma, but less than those with FeLV. Factors that appear to put cats more at risk for developing lymphoma than others are being a Siamese cat, a short-haired cat, a male cat, or a cat that’s exposed to cigarette smoke, such as in the home. Cats over the age of 7 are also thought to be at considerably higher risk for developing the disease than younger cats.
Lymphoma is most likely to develop in a cat’s digestive system, as this is where the most lymphocytes are found in the cat’s body. However it’s important to note that lymphoma can appear anywhere in cats.
Diagnosing Lymphoma in Cats
If you notice that your cat is exhibiting any of the lymphoma symptoms, or they’re simply not acting like themselves, take them to the vet as soon as possible for an examination.
- Physical examination: Diagnosing lymphoma will begin with a very thorough examination. The vet will note the cat’s weight, their appearance, and will check for abnormal lumps and bumps. If one is found it will help the vet arrive at a diagnosis but often, palpation of the abdomen can seem completely normal, even in cats with advanced stages of the lymphoma.
- Blood tests: Unfortunately, there is no one single blood test that’s been developed to test for lymphoma. The only exception is when the cat has developed leukemia, a specific tumor of the lymphocytes. A vet can still perform however, a blood test to check for the complete blood count (CBC). This can show low blood albumin levels, mild to moderate anemia, and serum globulin antibodies. Through this blood test the vet can also determine if the blood cobalamine levels are low, or if the cat has an increased amount of lymphocytes in their blood. All of these factors can help the vet reach a diagnosis of lymphoma.
- FLV and FIV tests: These will be taken to determine if the cat has leukemia or an immunity deficiency. Because cats with these diseases are so much more at risk for lymphoma, a positive result on either of these tests will also point towards a lymphoma diagnosis.
- X-rays: These may also be taken but there is no definitive x-ray that can diagnose lymphoma. Instead, these will probably be taken to rule out other causes of the cat’s illness. Enlarged mesenteric lymph nodes, thickened walls of the intestines, increased mass present between the cat’s lungs, or a blurred abdominal image may all show up on the x-rays, also indicating a possible chance of lymphoma.
- Ultrasound: These will show your vet much more than the x-rays will. Ultrasound examinations can identify thickened walls of the cat’s intestines, enlarged lymph nodes, loss of normal intestinal layers, or a narrowing diameter of the interior of the intestines can all show up on ultrasounds and help the vet reach a lymphoma diagnosis. Ultrasounds can also help guide a needle into a possible tumor site so that the vet may withdraw some of the tissue and have them tested further.
- Endoscopy: In this procedure, a scope will travel through the cat’s digestive tract. The vet will use this scope to look for enlarged intestinal walls, abnormal coloration, and ulceration of the intestinal lining. Along with giving the vet a better look at what’s going on in the GI tract, an endoscopy can also allow the vet to take small pieces of tissue that can be withdrawn and analyzed.
- Microscopic examination of tissue samples: This is probably the most common test vets will use when trying to diagnose lymphoma. With this test, a veterinary pathologist will study any cells or tissue that has been withdrawn from a suspected tumor site to determine whether or not the cells are cancerous.
Treating Lymphoma in Cats
Treatment for lymphoma varies widely. It will depend on how advanced the cancer is (what stage it’s in), the cell-type involved, the overall general health of the cat, and the possible side effects of the drugs used to treat lymphoma. Here are some of the most common lymphoma treatments available.
- Small-cell lymphoma: When the disease is less aggressive and still in its early stages, it’s known as small-cell lymphoma. This is the most treatable form of the disease and during it, the cancerous cells have not yet strayed very far from their original genetic makeup, meaning that it responds better to different types of drugs. A combination of the drugs prednisolone and chlorambucil are typically given to treat small-cell lymphoma and they’ve been shown to dramatically improve the condition. When this happens, the effect can last for several years.
- Large-cell lymphoma: This is a more drastic, more aggressive, and more severe form of the disease. Unfortunately, cats diagnosed with large-cell lymphoma don’t typically have a very good diagnosis. Drugs can be administered to help treat this type of the disease, but they too are very aggressive and can cause some pretty serious side effects. The most common treatments for large-cell lymphoma are the drugs cyclophosphamide, vincristine, and prednisolone. They have been said to also extend a cat’s life for just 60 – 200 days.
- Radiation: This can be used to treat lymphoma, but it’s typically a “last-ditch effort” or rescue protocol when other treatments are no longer able to control the lymphoma. With this treatment a focused radiation beam will penetrate the isolated area of the body and try to destroy the cancer cells. It’s an expensive option, and one that may or may not improve your pet’s condition.
- Surgery: If there is just a single isolated lymph node that’s affected by the disease, surgery may be an option. Surgery is not recommended for the majority of lymphoma cases, as they mostly occur in the cat’s digestive tract, and performing surgery in this area may actually shorten the cat’s life.
- At-home care: Even while your cat is going through treatment they will likely still be spending most of their time at home. The important thing is that you try to keep them as comfortable as possible and allow them to have their space. Set up a room or corner with their bedding and don’t allow other pets in the household to use it. (Sick cats typically like to keep to themselves.) Make sure their food and water dishes are nearby and that these too, are designated only for the cat currently undergoing treatment. Also make sure that all family members are continually petting the cat and spending quality time with them. While they may not want to sleep with other pets, a soothing tone and kind word can go a long way towards making a sick cat feel better. Provide litter boxes that are easy-entry and in multiple locations around the house. Cats suffering from lymphoma often don’t like to use litter boxes so this will help both of you.
There are many different treatment options for lymphoma and not all of them might work on your cat. The ability to maintain or gain weight is the best way to judge whether or not the lymphoma treatment is working so keep a close eye on your cat and make sure to weigh them often while they’re undergoing treatment.
Here’s the story of Twitch. Twitch was diagnosed with feline lymphoma which was removed and followed up with a multidrug chemotherapy protocol:
Receiving a lymphoma diagnosis for your cats can be devastating. Remember though that there are non-aggressive types of lymphoma in cats, and that there are medications and other treatment options available for both types. Remember that through their behavior, personality and appearance, your cat will tell you if and when treatment is no longer working and it’s time to let them go. This is the most difficult decision a cat owner will ever make when it comes to caring for their pet, so be sure to discuss it thoroughly (and perhaps even over and over again) with your vet.