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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Common Cancer Mistake: Assuming Chemotherapy Is Not an Option

Updated: January 25th, 2021


Do dogs suffer during chemotherapy for their cancer treatments? This veterinary oncologist has an answer that might surprise you.

Many pet guardians assume that they would never, ever use chemotherapy to treat their dog’s cancer … and then change their minds.

Before I see new clients, I often chat with the primary vet and commonly hear “Zoey’s mom is against chemo, but I’m sending her over to learn about Zoey’s cancer and treatment options, but she is not interested in chemo.” Later, after our meeting, it is not uncommon for that same pet guardian to decide to treat with chemotherapy after meeting me. Am I hypnotizing these resistant parents?

Of course not. I’m just replacing myths with facts, and fears with hope and knowledge.

Fear: Chemotherapy Has Terrible Side Effects

We do not use the same high doses in dogs that are used in humans, and so 80% of animals that receive chemotherapy in my practice have no side effects. 15-20% of pets have mild side effects. About 5% of chemo patients have severe side effects that require hospitalization for 24-48 hours. Most patients are feeling better with IV fluids, injectable nausea meds and antibiotics. The next time we give that chemo drug, we use dose reductions and meds to prevent further side effects, and find that most patients have no issues – even with the same chemo drug that landed them in ICU the last time.

It is a myth that the pet will feel crappy all the time, that they suffer during treatment, and they will be hospitalized all the time. In general, pets on chemo feel good not just after chemo, but during the protocol.

Fear: Once You Start Chemo You Shouldn’t Stop

In human medicine, we expect patients to “soldier on” and tolerate chemo side effects. But that’s not the expectation in pet medicine.

Giving chemo to your pet is not a contract. If you do not like how your pet is handling it, you can stop. I never force people to continue, but I do encourage them to try a dose or two.

Most pet Guardians are so surprised and pleased at the lack of side effects that they return with their pet for more treatments. So meet with the specialist and learn about the options. That way, even if you decide not to treat, you will have made an educated decision. I have empathy for the frustrated Guardians I see who thought treatment wouldn’t be well tolerated, so didn’t start until they have exhausted other options — and then wish they had started chemotherapy earlier when they realize how well their dogs do on it.

Chemotherapy is one tool among many we discuss in The Dog Cancer Survival Guide. Pick up a copy of the book to find out more about how it could help your own dog.

Live Long, Live Well,

Dr. Sue

Leave a Comment

  1. Christy Parker on August 6, 2022 at 9:54 am

    Good afternoon. I have spent hours reading Dr. Ettinger’s blog. It has given me so much hope for my 7 yr old large mixed breed (pit bull/Rottweiler/jindo) she ha recently been diagnosed with osteosarcoma in her ankle. They said we caught it early but she also has a torn ccl. We are meeting with an oncologist Aug 8, 2022. Would love to talk to her or if there is a direct email or phone number for her.
    Thank you so much!

  2. Bernard Prevuznak on May 9, 2020 at 8:39 am

    Is there evidence of a dog surviving acute leukemia? For a period of time longer then 2 months…please give me some hope!!!…my 4 year old is on prednisone and CBD oil…along with a cancer fighting diet!

  3. Janice Wright on November 2, 2019 at 10:14 am

    I have been told that because we do not use the same strength of chemotherapy on our dogs as we do humans, because there are such bad side effects, we do not get the same results that we do in people. That is why oncologist know the patients “death date” so closely. It isn’t given to get rid of, but to extend the life for a short period of time. Is this true?

    • Dog Cancer Vet Team on November 4, 2019 at 9:09 am

      Hello Janice,

      Thanks for writing. Dr. Sue, the co-author of the Dog Cancer Survival Guide and an oncologist wrote this article called What I Would Do For My Dog With Lymphoma. In this article, she writes that “Dogs tolerate chemotherapy treatment so well that their life is considered good to great by most Guardians in my practice during the protocol and after the protocol (when they are in remission).” But each dog is different and may react to different chemo drugs in a different way. You can find more statistics on this here.

      Each veterinarian or oncologist is different, and not all of them have the same opinion on conventional or even alternative treatments. This is why Dr. D highly recommends knowing your personality type and to go through the various stages of Treatment Plan Analysis, so that you, as your dog’s guardian, can make the right choice for your dog.

  4. Aman Bansal on April 10, 2018 at 4:24 pm

    As per the vet, my dog is suffering from venereal tumour.. she has started her vincristine dosage and has taken her first dose 2 days earlier…. I think she is suffering tremendous side effect due to this.. her hair are constantly falling.. and she has not eaten a single bite of her food for 2 days..neither she is drinking water..i am getting very tensed for per me,I don’t think that she has tumour.. my dog has just 2 weeks before given birth to two puppies and I think that is the cause of her vulva expansion.. please help me

    • Hayley Andrews on April 17, 2018 at 9:20 am

      Thanks for writing and we’re sorry to hear about your pup. Please talk to your vet about the side effects your pup is experiencing. Your oncologist will need to know about these side effects to help you and your dog.

  5. Jayne on November 6, 2013 at 12:01 pm

    My dog was diagnosed with lymphocitic leukemia. We started her on leukeran (chemo pill) and prednizone. Within 9 days of treatment her heart murmur was much worse, she lost muscle mass, she had extremely labored breathing, she had no energy…….she was dying. I took her back to the vet’s office. Her regular vet was out. A different vet took one look at her and her blood counts and said get her off of the chemo and prednizone. They will kill her before the leukemia. She has been off for about two weeks. Each day further from the chemo treatment she is doing better. She is running and playing! Does she still have leukemia? Yes. She doesn’t know she has leukemia. We are taking each day as a gift. I am not sure how long we will have her, but her beautiful spirit is back.

    • Susan Kazara Harper on November 6, 2013 at 1:30 pm

      Hello Jayne, As you’ve realized, the most important thing is that your girl is enjoying life! And this is a classic example of some conventional treatments not necessarily being the best for every dog. There is however, so much that you can still do. You haven’t mentioned her nutrition, and there are many natural supplement (nutraceuticals) that have very beneficial effects both to support the dog and to help battle the disease. The Dog Cancer Survival Guide would be a great reference for you, covering all aspects of the coping with the dog cancer journey as well as nutrition, supplementation etc,. You can also download the free Dog Cancer Diet at the top of the blog, or at I’m glad your vet practice is working with you. Stay positive and enjoy your girl’s wonderful spirit!

      • Jayne on November 7, 2013 at 12:20 pm

        Hi Susan, Thanks for your kind message. Yes, two weeks prior to starting chemo, we found out from my dog’s preliminary bloodwork that there was something going on with her body. I started her on a healthier diet right away. Currently, we are using Primal. Also, I took her to a holistic vet for a second opinion. She put her on two supplements. I keep both vets informed so that we can work as a team. I had already downloaded the Dog Cancer Diet. Between all of the information, I hope we are taking the best path for my dog. Our pets are a precious gift and blessing.

      • Jayne on November 8, 2013 at 9:41 am

        Hi Susan, I replied yesterday. Not sure where it went. Thank you for your kind words. Anyway, after the preliminary bloodwork, we knew something was wrong. I changed her diet to a healthier diet of raw (Primal) and no carbs. This was two weeks before we tried the chemo and prednisone. I do have the free Dog Cancer Diet. I, also, got a second opinion form a holistic vet. She has my dog on two supplements. The regular vet, the holistic vet, and myself are working as a team. Pets are a big responsibility and a wonderful blessing!

  6. big john on October 24, 2013 at 8:25 am

    chemotherapy won’t cure humans and it won’t cure dogs – its all about the money and the profit in drug costs to the vet

    • on August 4, 2014 at 6:37 am

      Actually big john it did cure my dog of histiocytic sarcoma after having chemotherapy. He was cancer free for 4.5yrs and he was not sick at all during treatment or at any time after. It was business as usual and he had a great life. Of course he was treated by an oncologist who was able to give him the best treatment possible through years of experience in just the field of cancer

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