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

Things You Need To Know About Radiation for Dog Cancer

Updated: November 27th, 2018

This is a continuation of the previous blog topic, radiation therapy in dog cancer.

We looked at some benefits of radiation previously, both in terms of life quality and lifespan.

This time, I would like to look at some of the downsides.  I am not interested in painting a darker picture than is necessary.  This is a treatment where a rationale approach in needed, where good and bad are evaluated.  As an owner and guardian of your dog, you should be advised of things so you can make educated decisions.



Radiation therapy is no joke. Each treatment requires general anesthesia, and protocols for designed for cancer remissions involve multiple treatments each week, sometimes even daily. Multiple rounds of general anesthesia should be taken into account when making a decision about radiation, especially in senior dogs. Most vets would agree that an aged canine and 30 rounds of general anesthesia may not be a good mix.

Palliative treatment, radiation designed for the comfort (pain control) of the dog, is less frequent, perhaps weekly for a month or so. This seems a bit “easier on the system” overall.

The radiation in the beam, if it contacts other living tissue, will damage it as well. Sometimes there is radiation scatter, which is where the beam directed at the tumor actually ends up hitting a bit of normal (non cancerous) body tissue.

There can be some side effects that may be seen immediately following treatment, when the beam contacts normal body parts.

The skin can get a little inflamed, similar to a sunburn. There may be nausea, vomiting, diarrhea, and loss of appetite. If radiation contacts the mouth, irritation and sores may occur within mucus membranes lining the mouth. This can be painful and require care. If the beam or scatter contacts the gland that makes tears to lubricate the eye, injury can occur to the glands.  This  requires lifetime lubricating ointment to be put in the eyes. Similarly, the lining of the lungs can become damaged if they are exposed to radiation.

All of these effects can occur within days or weeks of radiation treatment and examples of acute toxicity.


Get a copy of the Dog Cancer Survival Guide to learn more about Dog Cancer and Radiation


Radiation consequences can occur years later…delayed radiation toxicity. This can include injury to kidneys, nerves or spinal cord, and ligament damage.

A bizarre delayed toxicity form is the development of new cancers, as a consequence of the radiation. This is documented with cases of osteosarcoma (bone cancer), bladder tumors, and connective tissue tumors.

Take home message? Radiation is not a minor therapy. Consider it carefully. Be advised if you have a young dog that you are considering radiation for, you may see delayed toxicity, years later but during the dog’s lifespan, even in the form of new cancers.

Discover the Full Spectrum Approach to Dog Cancer

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  1. Shannon George on November 2, 2018 at 3:41 am

    My 6 year old lab was diagnosed with partoid salivary gland carcinoma. We did surgery to remove growth and the test show no cells in surronding tissues. We were suggested radiation treatment or what and see. Anyone have any information on this type of cancer or advice?

  2. Robert Fullick on November 23, 2017 at 9:28 pm

    Hi I know this post is old but…our Labrador has an MCT in his front right paw…had surgery to remove it and lymph node, got clear margins around it but not depth so had radiotherapy- absolutely horrendous, and nearly lost him twice. Vets put a fentanyl patch on half way through and reacted really bad – couldn’t breathe and throwing up so rushed into ICU for 10 days (at £300 per day). Paw sloughed off, broke down completely – in the end looked like was dipped in glue, was gunky and for 4 months the vet didn’t want to feel like they had been beaten – now I know was complete ego trip – and my boy was in agony until we had to amputate 3 months ago. Total £18,000 and even now I’m struggling to pay as had to use credit cards and the last £700 I’m being hounded for. If I’d known now, I would’ve amputated at the first appointment!

  3. Laurie Jeffers on December 23, 2016 at 7:10 am

    My 6 year old cattle dog was diagnosed with a soft tissue sarcoma tumor in the upper inside elbow area. I had 2 treatment options: 1. amputate the leg and most likely the cancer would be cut out, or 2. administer 3 days of stereotactic radiosurgery and no amputation. We went with option one because of estimated costs. I feel I was slightly mislead during the consultation which in my mind lead me to choose amputation. The surgery DIDN’T obtain clean margins which now means my girl has lost her leg and now requires 19 days of radiation treatment at and additional cost that will surpass the more expensive choice of treatment option 2! Hindsight, I should have gone with the more expensive treatment (SRS) and could have saved money and more importantly, my dogs leg. I feel my hometown vets were more compassionate to my dog’s needs but they didn’t have all the necessary equipment so we had to travel 180 miles to an oncology clinic in a bigger city. In my opinion, my dog was looked more as “a number” than a “living patient”.
    Our dog is a therapy dog and we are now choosing to do a crowdfunding campaign to see if we can afford the radiation treatments. Remember, you are your dog’s advocate. Please do your research, get written estimates and ask lots of questions during any vet consultations.

  4. Susan Kazara Harper on October 23, 2014 at 7:13 pm

    Hi Hayley,
    Bless you and your dog to go through all this. I know it’s hard; remember that chemo and radiation for dogs is nothing like the doses used for humans. That doesn’t make it any better when you know he’s not feeling well. You don’t say what his symptoms are, so it’s difficult to help you along. Have you been back to the vet to ask? If your dog is not eating, it’s possible to use gentle appetite stimulants to help get that food in, and I hope you’re using the Dog Cancer Diet. It’s important to ask your vet, or vet oncologist what side effects to expect, how to help him through, and when to know if it’s a stronger reaction than expected. You must remember as well that he’s going to reflect your own emotions. For him, you must stay gently positive, offer play when you can, perhaps even offer him that good, natural food by hand; it’s so much more important when we hand-feed when they’re not feeling well. Do check in with your vet to help any symtoms, and keep reminding your boy that you’re in this together and doing everything you can through your love. He looks to you for the mood of the day, and the more positive you can be, the better he will respond to everything. Good luck!

  5. Hayley on October 15, 2014 at 6:13 pm

    Hi there, I have a 3 year old Bloodhound going through chemo and radiation everyday. He’s in his 4th week and its hitting him pretty hard. Do you know of any tips that are helpful and more “natural” to make him feel better after his treatments? Maybe like heating pads, a type of food or anything. Just hate seeing him feel like this and love him so much i just want to find anything that could help in the least bit through his post daily treatments. I know whats he’s going through is unbearable and I can’t even imagine what he feels like since he’s just a puppy- but I’m just desperate.

  6. Troy Daniels on August 13, 2014 at 12:41 pm

    I have a 12 year old Standard Poodle. She has had two surgeries in the last five weeks. Otherwise she is in very good health. The vet said that she is a “special animal.” While I agree, I’m trying to decide what is best for her. She lost all of her front upper teeth and canines, she has had persistent infection in her mouth and gums since this started. She was on multiple antibiotic regimens. She had her teeth cleaned by the vet every year for the last several years, everything checked out as normal less than a year ago. The cancer seems to be fairly aggressive. She has been diagnosed with Squamous Cell Carcinoma. Our vet does not do radiation, but has recommended that we consider it with a referral. Our vet has indicated that we are looking at a year at most. Given that we have a year, I am concerned about quality of life. How would you proceed?

  7. Lisa on October 19, 2013 at 5:52 pm

    My Name Is Lisa My ,4 Year Old Rottie Bru Has A Growth Inside His Spinal Cord That Can’t Be Biopsied And Can’t Be Removed I Have Done Some Chemo Treatments Inflammatory Treatments And All Anti Fungal Treatment And He Isn’t Any Better My Next And Only Option Left Is Radiation What’s Your Opinion?

  8. Victoria Tyman on April 30, 2013 at 12:17 pm

    What are the odds of obtaining clean margins when removing a mast cell tumor from a dog’s front leg (inside of “elbow” area) ?

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