Conscious Cat

October 24, 2011 342 Comments

Chemotherapy for Cats

Posted by Ingrid

Feebee cat in blue chair

While cancer in cats is not as common as it in dogs, it is still one of the leading causes of death in older cats. According to the Animal Cancer Foundation, 6 million cats will be diagnosed with cancer in the United States along. And because cats are masters at masking illness, it is often harder to detect.

Cancer used to be a death sentence for cats, but recent advances in feline cancer research have made treatment possible in many cases. Just like with human cancers, early detection is key to successful treatment.

Treatment options for cats are almost as varied as treatment options for human cancers, and will depend on the type of cancer. Surgery is the most common treatment for any lumps or growths that need to be removed. In some cases, surgery can be curative. Other cancers may require chemotherapy or radiation.

How chemotherapy works

Chemotherapy uses drugs with the objective to kill cancer cells with the least possible amount of damage to normal, healthy cells. In human medicine, the goal of chemotherapy is to achieve a cure. In cats, chemotherapy is aimed at controlling the disease and achieving a period of remission for the cat. Chemotherapy is typically used for cancers that affect multiple sites. Lymphoma is the most common form of feline cancer that is treated with chemotherapy. The drugs used in veterinary chemotherapy are frequently the same drugs used in human medicine.

Most cats tolerate chemotherapy well

Most cats tolerate chemotherapy well. Some cats may experience side effects such as vomiting, diarrhea or poor appetite, but these side effects are usually mild and can be managed with supportive care. Only a very small number of cats on chemotherapy will require hospitalization due to the side effects of chemotherapy. Unlike humans, cats will not lose all their hair. Most cats will lose their whiskers, and shaved hair will be slow to grow back, but substantial hair loss is uncommon.

Support your cat’s immune system

It is important to support your cat’s immune system while she is undergoing chemotherapy. One of the foundations of a healthy immune system is diet. Typically, veterinarians recommend a high protein, low carb, moderate fat diet for pets with cancer. A high quality grain-free canned diet will probably be your best choice for your feline cancer patient.

Even though I’m a proponent of raw feeding, I’m on the fence as to whether raw diets are appropriate for cats with cancer. On the one hand, there are numerous anecdotal reports of miracle cures when pets with cancer were fed a raw diet, on the other hand, I don’t know whether feeding a raw diet to an immunocompromised pet is necessarily a good idea. Check with a veterinarian who is familiar with raw feeding whether a raw diet is appropriate for your cat while she is undergoing chemotherapy.

Supplements and herbs

Supplements and herbs can provide immune system support during treatment. Probiotics not only help maintain a healthy gut flora, but also boost the immune system. Anti-oxidants and increased amounts of omega-3-fatty acids may also be indicated. Check with your veterinarian to determine which supplements are indicated for your cat.

Supportive therapies such as acupuncture, Reiki or other forms of energy healing can support your cat through her treatment. These therapies will not interfere with conventional medical treatment.

How will you know whether chemotherapy was successful?

A cat in remission doesn’t look any different from a cancer-free cat. Typically, a successful remission means that lymphnodes will go down to normal size, and if there were any signs of illness that were related to the cancer, they will disappear. Remission can last anywhere from weeks to months, and for some lucky cats, even several years.

My personal experience with feline cancer

My first cat, Feebee, was diagnosed with intestinal lymphoma when he was 15 years old. He tolerated his chemotherapy protocol of a combination of Vincristine injections and oral Cytoxan and prednisone well. He would be a little subdued for about 24 hours following treatment. His appetite wasn’t that great during that period, and he slept a lot more than usual, but the rest of the time, his quality of life was good.

After seven months, he stopped responding to the chemotherapy. My vet gave me the option of continuing with more aggressive drugs with the potential for more severe side effects. I elected euthanasia. My little man confirmed that I made the right decision: he died in my arms while my vet was on the way to my house.

Being faced with a cancer diagnosis is a devastating blow for cat parents. Making a decision about treatment is as individual as the affected cat and her human. There are no hard and fast rules. The ultimate goal of any decision is to provide good quality of life for the cat for as long as possible.

Have any of your cats undergone chemotherapy? What was your experience?

Photo ©Ingrid King

Dr. Goodpet



342 comments to “Chemotherapy for Cats”

  1. Laura Peck says:

    I would like to know if the editor has a list of “best” feline vets, particularly surgeons, in the US. We have had 2 cats who subsequently died from stomach cancer, and I want to be prepared to travel if/when it ever happens again. I would also like to know the link, if any, between clumping litter and cancer in cats.

    • Chari says:

      It’s funny you say that because when my cat was diagnosed with stomach lymphoma on Dec 8/14 I tried to think about what in my environment could have caused it. The only thing I could think of was either his food, or his clumping litter that I have always used. My spouse wrote to ‘arm and hammer’ as this is the brand of litter we use. We did receive a fast response saying they do many toxicology tests before anything goes to market. I left it at that. My cat who has cancer just turned 14 yrs old, but the thing is I have a 20 yr old cat who has never had cancer, and I’ve had the 20 yr old since he was 1 yrs. The only difference between the 2 cats is that the one who has cancer has only ever preferred to eat dry food, while my 20 yr old mostly likes wet. Could it be the dry food? I don’t know that we’ll ever know….

      • Robin says:

        I inherited 2 cats 3 1/2 yrs ago when they were almost 11 yrs old and one of them was diagnosed with small cell last year. The house they had been at for their first 11 yrs had chain smokers in it. I could rarely visit because of the smoke/smell. Not only did these cats get a good dose of second hand smoke, when they cleaned their fur, they were also swallowing the carcinogens. They tested negative for feline Leukemia which can be a cause of lymphoma so his vet says the exposure to the smokey environment he was in caused it. So far, his sister is fine.

        • Ingrid says:

          When I worked in veterinary clinics, clients who were smokers would often quit smoking after the vet explained the health risks of second hand smoke for their cats. I always found it interesting that they wouldn’t quit for their human family members, but when it came to putting their pets at risk, they did!

      • Ingrid says:

        There are so many things that can cause cancer, it’s really impossible to pin it down to any one thing. The best we can all do is to eliminate as many things as we can that we have control over, but then there’s still the issue of genetic make up as well as things in the environment that we can’t control.

    • Ingrid says:

      Much as I would love to have a database like that, I think it would be impossible to compile that information, Laura. Your best bet for finding a good feline vet is the American Association of Feline Practitioners’ website. For specialists such as oncologists, clinics affiliated with veterinary schools will usually be up to date on the latest information.

  2. Laura Peck says:

    I have always been concerned about the chemicals. I read the book, Cat Daddy, and he stated that clumping litter could cause cancer because it contained silica. This resurrected my concerns. I mix the clumping litter with regular litter, but the dust remains on the cat’s fur. When they bathe, they ingest the dust/chemicals. It is great for clean-up and odor control, but if there is documented evidence that it can or does cause cancer, I will make whatever changes are necessary.

  3. Laura says:

    Thank you. Agree. Not the clay litter I worry about but the silica (glass) from the clumper.

  4. Chari says:

    I am not sure what to do. My spouse took Roach in for this first blood test since starting Leukeran 2 mg 3X per week and found his white blood cell count was low. I didn’t speak with the vet but the vet told my spouse to take him off Leukeran for 2 weeks then bring him back. He is taking 10 mg of Prednisolone every day and Remeron x2 a week, and Pepcid AC every day. So what now? I know the Prednisolone does not destroy cancer cells so I don’t know why the doctor wants me to bring him back in 2 weeks. Has anyone had this experience?

  5. Michelle says:

    Chari, I believe what I know will help, though Kallie’s situation isn’t exactly the same. Prednisolone reduces the inflammation in the intestines and stomach. Traditionally, it’s used with chemo for maximum effect. Kallie’s white blood cells were off after a month of Luekeran, every other day 2 mg, so the vet changed the regimen to 2 mg every third day. That did the trick. Based on that, I am not sure why the vet is completely stopping the chemo. However, I wonder if the vet wants to detox the cat then check his blood in 2 weeks to ensure the white blood cells are normal. I recommend you talk to the vet .

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