Chemotherapy for Cats

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

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549 Comments on Chemotherapy for Cats

  1. Angie
    August 19, 2016 at 9:54 pm (1 week ago)

    Wow great website. Our cat Monet just had surgery for radical mastectomy last Tuesday. We just started our first round of chemo today with Adriamycin and Cytoxan. This is our 2nd round of surgery since May 2015. Out vet felt surgery went well however the BB size pellets located further in the upper armpit were in muscle and could not be all removed. She’s such a sweet and affectionate cat (aren’t they all!), but seems to be getting back to her self. I’m open to any advice for feeding, supplements and advice anyone has. Has anybody used and of the Wellbeing Cancer care supplements?
    Looking forward to hearing from others and prayers to those on the board with cats that are ill. Thank you!

    • Dovemck
      August 20, 2016 at 8:09 am (7 days ago)

      All the best to sweet Monet and to you too. Our journey is so different from yours that I can’t offer much more than sympathy and best wishes. My Boofy has small cell lymphoma (GI) and on round 7 Leukeran, doing well but liver enzymes still stupid high. She may have liver cancer but it’s acting atypical. We’re using Denosyl atm which is prescription liver tonic. I too would love to hear how others have done with supplements to support prescribed treatment.

    • Kelly Waters
      August 20, 2016 at 2:48 pm (7 days ago)

      My Duke was diagnosed with Hemangioscarcome at the end of June. Hes taking I’m Yunity (turkey tail mushrooms), tumeric (natural inflammation reducer), and omega 3 fish oil. We’ve changed him over to a clean diet, trying to be grain free. (Carbs feed cancer) Hes also doing ozone therapy once a week, except on weeks he does chemo. (Every 3 weeks). I asked his oncologist about trying eastern medicine and she was so hesitant. She sent us to a vet she’s knows who practices eastern medicine. Between the 2 doctors, I feel like there’s no stone we haven’t turned.

    • Kelly Waters
      August 20, 2016 at 2:50 pm (7 days ago)

      Also, don’t be surprised if your fur baby starts losing whiskers. My oncologist prepared me for it, but said it’s pretty rare. Duke only has about 5 long ones left, but everyone has reassured me they’ll grown back.

  2. Jamie S
    July 15, 2016 at 6:40 pm (1 month ago)

    Hi! So glad I found this. Our Munch has been diagnosed with large granular lymphoma. We haven’t been able to find a lot of information on it, and apparently it is rare in cats and is relatively aggressive. We are fortunate to have an animal oncologist about an hour away so we can try to help her beat this. We are fighting so hard for her, and she has been a real trooper through it all. She has been poked and prodded more than anything or anyone should. My husband and I are mentally exhausted waiting for phone calls/lab work and vet appointments. Recently Munch has started losing her fur. Everything I read says she shouldn’t. Is that something to be concerned with? Just wait until her next appointment? These are the things we worry about all day. The good news is, she is relatively young. Only 9 yrs old. She eats so much. I’ve been told that is a good thing. She is rating almost 2 full cans of food a day. We have been giving her earthborn holistic food. And basically anything else she wants. Has anyone else had experience with this form of cancer in cats? We are open to any suggestion to help her through this. We love her so much and can’t imagine life without her.

    • Ingrid
      July 16, 2016 at 5:34 am (1 month ago)

      It’s rare that cats lose their fur during chemo, so definitely mention this to your oncologist. My experience with my own cat was that while he didn’t lose his fur, the hair in the areas that were shaved for ultrasounds never grew back (he had intestinal lymphoma and lived for seven months post diagnosis with a chemotherapy protocol of Vincristine and Leukeran.) All my best to you and Munch.

  3. dovemck
    July 7, 2016 at 8:13 am (2 months ago)

    I haven’t tried any supplements and Boofy is still leaking liver enzymes. We’re on a strong course of clav /antibiotics until the next round of pill chemo. I’m interested to hear what a holistic vet recommends. Please keep us posted on your journey.

  4. Adrienne
    July 6, 2016 at 12:48 pm (2 months ago)

    My situation is similar to Kristy’s. Midge had a tumor removed from his lower intestine in May, rebounded fantastically, and had his first four chemo treatments without incident. Took a week off, had a session last week with Vinscristine and totally crashed. He is right now in the hospital on IV fluids. I don’t know whether he has sores in his mouth/ throat but he won’t eat or drink. Lost all the weight he put on in the last month. The vet doesn’t know whether it’s a really bad reaction or whether the lymphoma has returned. So upsetting. I have returned to this board a number of times over the past month, and thank everyone here for the info sharing and support.

    • Ingrid
      July 6, 2016 at 4:16 pm (2 months ago)

      I’m so sorry to hear this, Adrienne. All my best to you and Midge!

    • dovemck
      July 7, 2016 at 8:09 am (2 months ago)

      Kepping both of you in my thoughts.

      • Adrienne
        July 7, 2016 at 1:56 pm (2 months ago)

        Thank you Ingrid & “dove”. Sadly, the vet did bloodwork and Midge’s kidneys have failed. I don’t know whether this was due to the chemo or not. A couple of months ago he had the beginnings of CRF but nothing alarming. We don’t believe he will pull out of this crash, as his body temp is falling. We are on our way shortly to see him over the bridge and out of pain. Again, thanks to all who make this a wonderful resource for us cat lovers. x/ A

        • Dovemck
          July 7, 2016 at 8:59 pm (2 months ago)

          Run free Midge, still young and beautiful. Give my love to Nessa who will undoubtedly show you the best sunny spots to nap in shadow of the rainbow bridge.

        • Ingrid
          July 8, 2016 at 5:43 am (2 months ago)

          Oh Adrienne, I’m so sorry.

  5. Kelly
    July 6, 2016 at 12:40 pm (2 months ago)

    My sweet 11 year old tabby, Duke, was diagnosed with Hemangiosarcoma last Wednesday. He was fine, and then one day started hiding and couldn’t walk. After 2 consecutive days at the pet ER, the doctors found a mass in his colon. We had it removed on the 24th, which is when the doctors found out the mass had been bleeding. Duke had a blood transfusion the next night. (This was super scary, because he’s a rare blood type and no one in Sacramento had his blood. Thank God for blood banks.) He has been recovering at home ever since. He was a little tired at first, but he has his appetite back, and is using the bathroom just fine. Tomorrow, we start chemotherapy, and I’m very torn about the decision I’ve made. There’s not a lot of research or information on felines with Hemangiosarcoma, so Duke’s oncologist is reluctant to try out any type of supplements. I’ve gone ahead and made an appointment with a holistic vet, which was recommended to me by a fellow cat Mom, I found on instagram, going through the same thing. The more information I can get on this cancer would be greatly appreciated.

    • Ingrid
      July 6, 2016 at 4:16 pm (2 months ago)

      I’m sorry about Duke, Kelly. All my best to both of you, and please keep us posted.

      • Kelly
        July 9, 2016 at 1:30 pm (2 months ago)

        Duke had his first round of doxorubicin chemotherapy last week, and he handled it like a champ. The new ultrasound showed thickening of intestines, which could be inflammatory bowel disease or swelling from his surgery. The Oncologist has recommended a different Integrative Medicine specialist. I have a consultation with the doctor on Wednesday. I believe they’re going to try acupuncture and ozone therapy. I will keep everyone posted.


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