Conscious Cat

October 24, 2011 134 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



134 Responses to “Chemotherapy for Cats”

  1. Nancy Burgeson says:

    Hello there everyone, I am so glad I found this site tonight! We found out just 3-1/2 weeks ago our Belle has Lymphoma. She had a mass removed on her intestine but also has one that can not be removed. This has been the worst summer of my life! First my husband had a serious back surgery and then 7 weeks later I had rotator cuff surgery and am recovering from that. On May 31st we lost our 19 year old maine coon Willy to renal failure and dementia. I thought I was going to die as he was the love of my life. Then as I mentioned above just a couple weeks later we get hit with this and our little Belle who is 14 years. I had pretty much given up hope as she has been so very ill. Today my husband and I made the choice to try chemo and all of this posts have helped me to realize there may be hope for her too.
    Thanks so much folks!

    • Ingrid says:

      Oh Nancy, what a rough year you’ve had. All my best to Belle – let us know how she’s doing!

    • girlfriday says:

      My cat was also diagnosed with cancer a few weeks ago and unfortunately she passed as the cancer was so advanced but through research I found some holistic treatments for her. Maybe they will help you. They can be used in conjunction with chemo. Won’t hurt to try, right?

      • Ingrid says:

        I’m sorry about your kitty. I would be cautious using any type of holistic treatment without running it by your cat’s oncologist and/or holistic veterinarian. Herbal remedies in particular can interact with conventional drugs.

    • karen murray says:

      I grieve for your loss, and prayers to Bast for the success of the chemo. we recently helped send our oldest boy, 18+yrs old, Ra to the bridge, he had renal failure for over 2 yrs, then recently heart failure, he left on 8 apr….then on 25 apr mama cat was breathing hard, at this time she was diagnosed w/ heart failure…amon & a half later I took her back for breathing to fast, this time what the dr pulled off her chest was about 100cc of milky stuff it was lymphoma, the x-ray shows a lg spot on her rt side….we didn’t discuss chemo, I guess it is the size of the mass & that she is between 17 & 19. bless u and your family, I hope it works for you

  2. Liz Hardy says:

    A really interesting article, Ingrid; thanks so much. I agree with your raw feeding caution for cats with cancer – it depends how their appetites are, and whether you are adding meds to the food.

    As I’ve found with my own experience with my stripy little Moofy and her tumor (and the many cat guardians I talk to via the Meow Cancer Clinic), every furry little cancer patient is different – and the first rule has got to be Do No Harm.

  3. Mariza says:

    I am so glad I found this site
    We are still waiting on the blood test results to confirm the diagnose of small cell lypmhoma on Ginger intestine. We are devasted and lost. She just turn 13, she is very active and she have good and bad days, some days throw up and every day diarhea .
    Depending on the results we already decided that we are going to put her thru chemo. Though decision but I believe that she is a warrior and she will go thru this just fine. I can’t even imagine our life without her, she is such a playful, loving cat, she even has a little heart on her nose :)
    When I first got her she use to fit on my hands, she was so tiny.
    My heart is broken and I don’t know what to do.
    When are they going to find a cure for human and animal cancer God?

    • Ingrid says:

      All my best to Ginger as she goes through treatment, Mariza. Keep us posted on how she’s doing!

    • Robin says:

      Small cell lymphoma is very treatable. I give my kitty his chemo drug (3 pills)every 2 weeks and he is in total remission since last Jan. He regained all the weight he lost and to watch him, you’d never know he had lymphoma. Animals don’t usually get the side effects we think of when humans get chemo. From the tons of research I’ve done, they might lose their whiskers(mine didn’t )and might feel a little nauseous the day or two after getting the dose, but that is very treatable with an anti nausea pill. It was very scary when the diagnosis was finally made. For 2-3 months, he had a feeding tube, so I could get nourishment I to him. It was definitely worth those few months of difficult until his diagnosis was made and I brought him to an Oncologist. She made all the difference I. The world and changed his meds to the new “pulsing method” which means every 2 weeks instead of a more frequent low dose. There’s a very informative and active yahoo group for feline lymphoma where you will also get a wealth of info. It’s a scary diagnosis but is treatable!

  4. Susan says:

    I am too very happy to find this website. My male cat, Baby, who is part Maine Coon and was a rescue has diagnosed back in February with lymphoma. He did really well on just a low dose of steriods for 4 months and then the vomiting started again. We just started him on a stronger dose of steriods and chlorambucil, which is very affordable. So far he seems like he is doing well. Still eating and only a minor loss in energy. He did urinate outside of the litter box this evening in the bathroom on one of the bath mats. I hope this isn’t going to be a re-occurence or issue with the medications. If anyone knows of any other side-effects to be wary of, please let me know. I’m really hoping that this regimen of medication will put the lymphoma into remission. I can’t imagine my life without my wonderful boy. Wishing all the other readers the best with their cats too.

    • Ingrid says:

      Contact your vet about Baby urinating outside the box, Susan. It may or may not be related to the medications, but in a cat with cancer, it’s important to address any potential medical issues immediately. All my best to your boy!

    • Robin says:

      I’m glad your kitty was started on Chlorambucil. Steroids alone will not treat lymphoma. Initially, my kitty was on both and had to be weaned off of Prednisolone because it caused him to become diabetic. Eventually, the diabetes did go into remission, so he’s been on only Chlorambucil since the end of Feb. He’s been in remission since being switched to the every 2 week pulse regime last Jan by his oncologist and is back to being a thriving happy kitty. For the first month (Dec)he was on Chlorambucil twice a week and did not respond. Early on, he started urinating beside his box. As he stabilized and went into remission, that behavior stopped. He hasn’t done that since the end of Jan. His oncologist also put him on a stool softener, because chemo drugs usually cause constipation. My thoughts were that either he didn’t feel well enough to be sure footed to stand in litter or that he was constipated(which he was), and again, wanted a firmer surface to stand on. I accommodated him by putting 2 large plastic bags flat next to his box with a few paper towels on top. This kept it controlled and I just folded it up and put fresh supplies down after he went. He did use his litter box as well during this time and it was a problem every so often for about 3 weeks. Once he was feeling better, he stopped this behavior. I still, to this day, put the bags/paper towels there. After not going there for 5 months, a few weeks ago, he did deficate a tiny bit and it was very hard which told me he was constipated. I increased the number of times each week he gets the stool softener and he hasn’t done it since. He is still eating well and acting normally so I wasn’t concerned that anything else was wrong. He also gets a 4-6 week checkup with his oncologist and his blood work has been fine. You could also get training pads at the pet store instead of the bags.

  5. Jeanette says:

    Our kitty Sugar was diagnosed with feline mammary cancer in January 2013. After her mastectomy chemo was not recommended, but she had a local recurrence 3 months later so after that lumpectomy chemo was recommended. She had 5 rounds of doxyrubicin and did great. She was never sick, in fact you would not have known she had cancer or that she was having chemo. Her only side effect was losing a few long whiskers which grew back. She was in remission for a year and shortly thereafter we found cancer in her lungs and chest and she made her bridge journey last May. I have no regrets about giving Sugar chemo. It is not the same as giving chemo to a human.

  6. Jeanette says:

    Our kitty Chai was diagnosed with small cell GI lymphoma in August 2013. Initially we gave her Leukeran (chemo) in pill form 2mg every 3 days. She did not tolerate it well – she was very lethargic, weak and had no appetite. We gave her a short break of a week then tried 1 mg of Leukeran every other day. She is tolerating that regimen very well.

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