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

My Experience with CyberKnife RadioSurgery

Updated: November 15th, 2018

In my last post, I introduced CyberKnife RadioSurgery, a type of stereotactic radiosurgery (SRS). This is the radiation unit we have at my specialty hospital, the Animal Specialty Center in Yonkers NY. I want to tell you a little bit more about my own experience with this new technology, but first, a quick recap on what this machine actually does.

CyberKnife, or SRS, can conform to the tumor: a radiologist can program its beams to closely follows the edges of the tumor, making it very accurate and much less likely to damage healthy tissue in the area around the tumor. It has multiple beams, and the robotic arm that holds the machine can position it in many more treatment angles. This combination of more beams and more positions means it treats with millimeter to sub-millimeter accuracy. This is why less normal tissue is radiated, a higher dose of radiation is delivered to the tumor, and fewer treatments (1 or 3 total) are needed. Fewer treatments means fewer trips to the hospital (conventional radiation treatments require fifteen to twenty sessions) and much lower risks from the required anesthesia.

CyberKnife RadioSurgery is used INSTEAD of surgery, when traditional surgery with a scalpel blade is impossible or would cause unacceptable side effects to the patient, or when surgery is refused (like an amputation for bone osteosarcoma). CyberKnife can also be used if conventional radiation has failed.

So what tumors have we treated and what are some of our experiences at Animal Specialty Center?

We treated our first case on March 7, 2008 and we have treated over 430 cases since then.

Brain tumors account for about 50% of our cases.  To date, we have treated 230 cases, including 110 meningiomas. After we had performed enough radiosurgeries to analyze them from a statistical standpoint, we did a study looking at 63 cases (53 dogs and 10 cats). The overall median survival time was about 15.5 months. This compares favorably to other treatment options, including radiation, conventional surgery, and surgery with radiation. That’s good news. Even better news is that we had very minimal side effects and fewer treatments to get these results.

The second most common tumor type we treat at Animal Specialty Center is tumors in the nasal and/or sinus cavity. To date we have treated 94 cases, including 79 dogs. In a study soon to be published which looks at 19 of those dogs, the median survival time was 13 months. This is comparable to conventional radiation, but, again, with very few side effects. (With the 15 to 20 conventional treatments, there is more radiation burning and inflammation to the mucosa lining of the nose and mouth.) One downside, however, was that dogs commonly experienced several weeks of congestion with CyberKnife.

The third most common tumor type we have treated is bone tumors. We have treated 44 cases to date. The outcomes haven’t been as uniform across the board, but for dogs with osteosarcoma in the limbs, we are seeing better survival times in “good candidates” – patients with enough bone structure left that they are not close to fracture.  For CyperKnife surgery to really help save a limb, there had to be enough bone structure intact to keep the leg from fracturing. What hasn’t changed is that chemotherapy after CyberKnife is just as important as chemotherapy after amputation to delay metastasis and for long term survival.

Finally we have treated various other tumors including oral tumors (best for ones of the upper jaw or maxilla), spinal cord tumors, thyroid carcinomas, prostatic carcinomas, and a non-surgical anal sac adenocarcinoma.  I am excited that we have treated so many more cases since our first two studies, and we look forward to publishing more data as we go forward.

Based on my experience, CyberKnife RadioSurgery, or stereotactic radiosurgery (SRS) is the treatment of choice for brain tumors and nasal tumors. The precision involved in radiosurgery is amazing, and we can treat our patients in 1 or 3 treatments (done on consecutive days). That means five times less anesthesia, five times fewer trips to the hospital, and fewer side effects. And the results are comparable to traditional radiation therapy.  Like you, I want dogs and cats with cancer to live longer and live well. CyberKnife definitely accomplishes that.

I feel so fortunate to be part of the CyberKnife team at ASC. We were the first to offer this to pets, and it will be great as this becomes more commonly available at other clinics around the country.


Dr. Sue


Leave a Comment

  1. JenM on December 30, 2013 at 6:42 am

    Hello! I have a 7 year old black lab mix with a chondrosarcoma attached to the base of his skull. The docs at CSU have recommended CyberKnife as one of the treatments options for him. We have been planning to start treatment this week.

    Do you have any experience with CyberKnife and this type of cancer? I’d also love to know if you have any advice on how we can prepare him over the next few days for both the anesthesia and radiation.

    And, lastly when is the best time to start him on an apoptogen?

    Thank you for your help and support!

  2. Joe on December 2, 2013 at 2:25 pm

    My question concerns the follow-up treatment of a nasal tumor treated with cyberknife.

    I have a 14 year old dachshund who had an advanced nasal tumor. The tumor was treated with cyberkife in August of 2012. The tumor did not enter the brain cavity nor did it get into his lymph nodes . His recovery was fast and the treatment seemed to work flawlessly. With later check-ups, there was no sign of regrowth.

    About one year later, his nose began to bleed. It is a constant slow bleeding, with much mucus. The blood is always encased in mucus. Some days and nights are better than others. I was told he would always have a bit of a stuffy nose. Is chronic bleeding common? Is there anything that can be done to help with this issue? I’ve been hesitant to have his nose scoped because of a heart murmur and potential trauma to him from the procedure.

    He is now on the lowest dose of metronomic therapy for the past month as a preventative measure. His blood has been checked twice so far and his CBC is perfect. If it were not for the bleeding and difficulty in breathing (mostly at night), he is full of energy and seems fine.

  3. Laura on September 23, 2013 at 5:44 am

    Hello Dr. Sue, I’m wondering if you have more information about TCC cases and cyberknife. My dog’s tumor is in the prostate and trigone area, and I’m curious as to how the average survival time and quality of life after treatment compare with chemo, NSAIDs and stenting… Any information would be appreciated. Thanks!

    • DrSueCancerVet on September 29, 2013 at 3:31 pm

      Laura, CyberKnife can be used prostate tumors, but we cannot give stereotactic radiation to the bladder, or any hollow organ like the intestines, esophagus, because it can lead to a perforation (hole). We have radiated prostate and combined with chemo, NSAIDS, and stenting when needed. Unfortunately this is a new technique for dogs so there is little published data to know what the increase in survival and response rate. Still we have found it well-tolerated in the dogs we have treated. Chemo is very important in these cases as these tumors are highly metastatic, and CK only treats the tumor in the prostate.
      All my best, Dr Sue

  4. Erika on January 29, 2013 at 8:42 am

    Hi Dr. Sue,
    Our chocolate lab Kaicee (13 years old next month) was diagnosed by Dr. Berg with a meningioma. Prior to the recent onset of seizures he seemed a fabulously healthy and fit dog. We are proceeding immediately with stereotactic radiiation, and I am grateful to have this option. I would love to see him reach 15!

    Thank you,

  5. Sarah Archambault on January 6, 2013 at 11:42 am

    Hello Dr. Sue

    I came across your blog in my desperate research to find a solution to my 5 year old pit bull’s tumor located in his spinal cord. We’ve done the MRI and even the surgery. Unfortunately our neurologist was unable to remove any of the tumor due to the location and it being a “bulky tumor”.

    Tomorrow we receive the results of the biopsy. We’re told that our dog either has lymphoma, a nerve sheath tumor or possibly a meningioma.

    When we got into this last week, we were hopeful that they would be able to remove as much as the tumor as possible surgically and then we could follow up with radiation and or chemo. Now that they could not remove any of it I wish we had known about the Cyber knife technology. Do you think this would still be an option for us?

    Thank you

    • Dr. Susan Ettinger on January 13, 2013 at 5:04 pm

      Sorry about your pitty! CyberKnife is an option for measurable tumors, like meningioma or nerve sheath tumors. If its lymphoma, conventional radiation is an option and CK is not really needed (you dont need conforming radiation for lymphoma, due to the way the cancer cells are so sensitive to radiation).
      What did the biopsy come back as? If you are interest in CK at my practice, let me know. Send me an email through my website,
      All my best, Dr Sue

  6. Shannon mccarthy on November 2, 2012 at 4:15 pm

    Hi, we are referred from the university of Guelph near Toronto to come for cyberknife. We will be driving. Does our dog go home with us at night or stay with the hospital?

  7. Bill on September 27, 2012 at 12:18 pm

    Hello Dr. Susan
    I spent three consecutive days at U.C. Davis last week having my dog treated for a tumor in the brain stem. I have a Neopalitan Mastiff and since his walking was being disrupted by the tumor, getting in and out of the clinic was heart wetching. But this week we have seen daily gains in his personality returning. He is 8 years old and the process was expensive but for my wife and I it came done to a quality of life for him. I was wondering if you have any statistics for survival rates for something like this?
    Thank you

    • Dr. Susan Ettinger on September 30, 2012 at 5:15 pm

      Hi Bill,
      Sorry about your mastiff. Was he treated with palliative radiation or RadioSurgery? It is hard to give you a prognosis without knowing much about the case. What were you told by the Oncology Service at Davis?
      All my best, Dr Sue

  8. Lucas Chesser on August 9, 2012 at 4:07 am

    My dog, Bailey, was recently diagnosed with prostate cancer which has invaded the adjacent lymph node. He’s a 10 year old Rotti and he was in excellent shape until now. We thought that there was not reason he could not defy the odds and outlive the average Rotti by 5 or more years. He never ate table scraps and was adjusted regularly. He does not have hip dysplasia, but he is a carrier of Erlichia. Our major downfall was in the diet. We fed (what I thought) was a high quality kibble diet. However, I now realize that there is no such thing.

    Because he was so healthy, we have elected to do the cyberknife. The oncologist seems to think that dietary changes should not be made until AFTER chemo. He said that the goal of the radiation is to create localized free radicals to kill the tumor. If you start pumping him full of antioxidants right now, it could counteract the radiation. The chemo will be traumatic, so he suggested that we should not change anything until after that.

    My experience is that you are never traumatizing a body by supporting health. But I understand the doctor’s concern. Is there a timeline for introducing the new diet? Have you noticed any significant problems with introducing it immediately? Also, what do you think about IV antioxidants for animals?

  9. Debby on August 2, 2012 at 10:27 am

    I just visited a cancer specialist here in S. Calif. and even though this technology is wonderful and does not require surgery, it is not affordable to Dog Guardians. Just the CyberKnife procedure is 12,500 dollars and that does not include chemo, bone scans, ct scans, and all the rest of the stuff that goes in to it. And as I understand all of this via the cancer vet, most of this treatment is done to reduce the pain and is never a cure. What are your thoughts?

    • Dr. Susan Ettinger on August 10, 2012 at 10:00 am

      Hi Debby,
      Unfortunately CyberKnife (CK) is expensive (here in my practice in NY it’s about $8000 for the CK including the CT scan). The treatment does help with pain but the goal is to damage the DNA of the cancer cells and kill them – for local control. Chemotherapy is to delay metastasis. A less expensive option is palliative radiation, which is typically weekly for 3 to 4 treatments. The goal of this is pain control, but it is a good option. Good luck!
      All my best, Dr Sue

  10. Michelle Yovanovic on July 25, 2012 at 1:08 pm

    Thank you for your valueable information. This sounds like exciting new options for treatment. My 9 1/2 year male english bulldog was just diagnosed today with a large macroademoma. Is there a particular size tumor that is too large for CyberKnife consideration? Thank you.

    • Dr. Susan Ettinger on August 10, 2012 at 9:27 am

      Hi Michelle,
      Thanks for your question. Technically size is not an issue, but risks of side effects does increase with larger tumors. If you are interested, feel free to email me thru my website and I can get someone from the Neuro Department at my practice to contact you.
      All my best, Dr Sue

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