CyberKnife RadioSurgery in Pets
Sue Ettinger, DVM. Dip. ACVIM (Oncology). Dr. Sue is a boarded veterinary medical cancer specialist. As a Diplomate of the American College of Veterinary Internal Medicine (Oncology), she is one of approximately 400 board-certified veterinary specialists in medical oncology in North America. She is a book author, radio co-host, and an advocate of early cancer detection and raising cancer awareness. Along with Dr. Demian Dressler, Dr. Sue is the co-author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity.
Updated: December 18th, 2018
If you have been following me on Facebook at Dr. Sue Cancer Vet, you know that last week I was lecturing with what I call “ASC Team CyberKnife.” This team includes radiation oncologist Dr. Sarah Charney, neurologists Drs. Rick Joseph and Jason Berg, and me, the medical oncologist. We manage all the CyberKnife patients that come to the Animal Specialty Center (ASC) in Yonkers NY.
So after work on two nights, we all traveled to Red Bank, NJ and then to Norwalk, CT to talk to veterinarians about CyberKnife RadioSurgery, what tumors it’s good for, and our experience over the last 4 years.
There is a lot of great information on radiation therapy in the Dog Cancer Survival Guide, but in case you haven’t read it yet, you should know that typically, radiation therapy is used for local disease control — to damage and ultimately kill the primary cancer, usually as a follow up treatment to surgery. For example, if a dog has an incomplete resection — which means that there are cancer cells detected in their surgical scar on the biopsy report (dirty margins) — we would follow the surgery with radiation treatments to “clean up” those microscopic cancer cells. This is pretty common when it comes to a mast cell tumor or a soft tissue sarcoma. These conventional radiation therapy treatments usually require fifteen to twenty treatments, which are also called fractions (see below). Each session requires a short anesthesia, and pets are usually treated daily Monday to Friday with the weekends off. That’s a lot of anesthesia.
Why SO many treatments? It’s all about the normal tissue in the radiation field. To minimize damage to the normal cells, the dose is divided up into many small treatments. These “fractions” are helpful because normal cells can repair themselves more efficiently after smaller, multiple doses. For example, if your dog has a tumor in the nose, conventional radiation therapy will probably expose other nearby body parts to the harmful radiation: the mouth, eyes, and brain may get radiation because it is in the treatment field.
It’s this damage to otherwise healthy tissue that has motivated oncologists to look for a way to deliver radiation with more precision, fewer side effects, and fewer treatment sessions. The new technique called radiosurgery aims at getting the radiation energy directly to the tumor – even inoperable tumors – while avoiding healthy body parts that might be damaged by the beam or by its scatter.
By the way, I personally think the radiosurgery name is silly because there is no surgery in radiosurgery. There is no actual cutting – the name is meant to imply that radiation is accomplishing what surgery would do if it could actually get to the tumor.
Radiosurgery is not good for every type of tumor (for example, mast cell tumors and soft tissue sarcomas are not good candidates). But it does offer hope to some patients whose tumors were once considered inoperable. Here’s why:
The new, modified linear accelerators (radiation therapy machines) can generate very controlled, narrow beams that deliver radiation very precisely. The machine has five “arms” and rotates around several axes. It can approach a tumor from almost any angle the radiation oncologist wants it to, and while a traditional linear accelerator has two to four ports (holes where the radiation exits), the CyberKnife has hundreds.
Planning the radiation is critical when you’re dealing with radiosurgery. First, a CT (computed tomography) scan is done to get a very detailed three-dimensional image of the tumor. (For brain tumors we need both a CT and MRI for planning.) Then, Dr. Charney, our radiation oncologist, uses a complex computer program to plan precise coordinates for the radiation beam.
The precision involved in radiosurgery is amazing, and it also makes radiation therapy more appealing to dog lovers. For example, a nasal tumor that requires fifteen to twenty conventional sessions and exposes the mouth, eyes, and brain to radiation can be treated in only three consecutive CyberKnife sessions. That’s five times less anesthesia, five times fewer trips to the hospital, and fewer side effects. And the results are comparable to traditional radiation therapy. Some brain tumors are treated in just one treatment. It is pretty amazing!
My practice was the first to offer CyberKnife Radiosurgery to animals, and we have been treating dogs and cats since March 2008. Currently, radiosurgery is only practiced at the University of Florida, Colorado State University, southern California, and my practice the Animal Specialty Center in New York.
In my next blog I will tell you what tumors we treat and our experience so far. Stay tuned – this is pretty exciting stuff!
Sue Ettinger, DVM. Dip. ACVIM (Oncology). Dr. Sue is a boarded veterinary medical cancer specialist. As a Diplomate of the American College of Veterinary Internal Medicine (Oncology), she is one of approximately 400 board-certified veterinary specialists in medical oncology in North America. She is a book author, radio co-host, and an advocate of early cancer detection and raising cancer awareness. Along with Dr. Demian Dressler, Dr. Sue is the co-author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity.
Dr. Ettinger,
Can the Cyberknife be used with a dog that was diagnosed with Leiomyosarcoma of the esophagus? Also what is the cost and risks of the treatments? What is the likely prognosis if treated?
Thank you,
Linda
Hi Linda,
Thanks for your question, typically CyberKnife is NOT good for hollow organs like the urinary bladder and esophagus, as there is a concern that the treatment if effective will result in a hole in the site. I obviously cannot make more specific recommendations over the internet, but in general, unfortunately CyberKnife is not the right treatment option for tumors in the esophagus.
Sorry, and good luck!
Dr Sue
I have a situation similar to what Tammy G. said on 6-27-12 (liver tumor close to vena cava.) Surgery was done but could not go too close to the vena cava. Have had a follow-up sugery to de-bulk the tumor while options are being explored. What are your thoughts on CyperKnife treatment, please?
Thank you,
Grace
Hi Grace,
Thanks for your question. CyberKnife can be considered for non-surgical liver tumors, but it depends on how close to the vena cava it is. We would need a CT to better know. Also there has to be measurable tumor for CyberKnife, not microscopic disease. For cases like this, it is case by case. You can contact my Oncology Service if you want more info on CyberKnife. After we have more info, I can discuss the specifics with our radiation oncologist.
Thanks, Dr Sue
Dr. Ettinger,
We live in Southern Indiana. The closest large city would be Louisville, KY which is about ten minutes away but we would be willing to do some traveling if we had a good option. We’ve been told the tumor is about the size of a cantaloupe.
Thanks,
Tim
Hi Tim, My radiation has some concerns about the size. Probably best to contact my Oncology Service if you want more info on CyberKnife and send us medical records if you are interested. After we have more info, I can discuss the specifics with our radiation oncologist. It can be considered on a case by case basis.
Thanks, Dr Sue
Our beagle mix has an adrenal carcinoma. If we can find somewhere that offers this nearby would she be a candidate? They tried surgery but were unable to remove any of it. The only option the current vet has given is chemotherapy.
Thanks,
Tim
Hi Tim,
Sorry about your dog. CyberKnife could be considered for a non-surgical adrenal tumor. It would depend on the invasion into the vena cava and the CT scan. Where are you located?
Dr Sue
Thank you for your response and concern. It is not clear whether my mother’s dog has a tumor or encephalitis and from what I’ve read online about others’ experiences an MRI might not definitively resolve the issue. My mother was concerned about being advised to have x-rays and a sonogram to rule out other issues before having the MRI. Her decision to proceed with medication seems to have been a good one. He continues to improve on prednisone and phenobarbital has resolved the seizures. I saw on the Apocaps website that only a smaller dosage would be advisable with his medication.
Dr. Ettinger, just saw your facebook page, saw a reference to stereotactic radiosurgery that seems to imply that CyberKnife is another name for stereotactic radiosurgery. Is that correct? If so, then I already know the answer to my question, which is that this procedure does not unfortunately work on bladder TCC.
Hi Chris,
I think you are referring to gas anesthetic, like sevofluorane, which is excreted through the lungs. Many universities and specialty hospitals like mine will use it for patients with complicated medical issues.
As for the name, CyberKnife is the brand name of our stereotactic radiosurgery unit. You may also hear to it as stereotactic body radiotherapy. It can get confusing!
Unfortunately tumors of the bladder are not good candidates due to risk of bladder rupture. However, we can use it for urethral and prostate tumors.
Thanks for your questions!
Dr Sue
My mother’s dog almost certainly has a brain tumor, since he exhibited the symptoms mentioned on the University of Minnesota website yesterday and the neurologist says it is either a tumor or inflammation. He was hospitalized for seizures and is cleared to come home soon since he has improved on steroids and seizure medication. My mother will make a decision on further diagnostics but after her prior dog’s liver cancer and the lack of success with surgery and treatment she wants to start with conservative treatment. It sounds as if Apocaps, Halo food and at least following the protein, grain and vegetable combination of the dog cancer diet would be consistent with reducing inflammation. If she was near the University or where cyberknife surgery is done she might be willing to do more. Both the vet and neurologist support the conservative approach but have not mentioned dietary changes. Are they appropriate under the circumstances?
Janice, Sorry about your mom’s dog. Advanced imaging (ideally MRI, or CT if MRI not available) of the brain can help figure out the cause of the seizures. Depending on your location, you may be able to travel for radiosurgery like CyberKnife.
I know it is hard when another pet had another cancer, because all the emotions get stirred up, but different cancers can have different treatment options and prognoses, so I hope you can get a diagnosis and make a good educated decision. There is no wrong or right decision, but it helps to get more info.
I’ve asked Dr D to address the supplements and diet question. Also remember there is a ton of info and emotional support in our book, the Dog Cancer Survival Guide.
All my best,
Dr Sue
A question, and a comment.
The question – is this procedure effective/useful on canine bladder transitional cell carcinoma?
The comment – that is a lot of anesthesia, but as you probably know, standard radiation therapy can take up to fifteen days of treatments as well, with anesthesia required each day, so, pretty comparable. When I took my pup to Washington State University for her radiation therapy, they were using what I believe was a newer anesthesia for a couple of reasons:
1. It was reversible, so the patient was only under for about twenty to thirty minutes, and when they woke up, the effects were pretty much gone.
2. It’s excreted through the respiratory system, not the veinous system, so, basically, the way it was reversed was that the dog just breathed it out.
On the downside, it was apparently more expensive than the anesthesia that they’d been using previously, but the increased cost was pretty much negligible, and the benefits were undeniable. My pup handles anesthesia EXTREMELY poorly, and every day when she came out from her treatments, she was trotting along with her tail wagging, behaving pretty much as if she’d just woken up from a very satisfying nap.
Unfortunately, I can’t recall the name of the anesthesia, but if anyone is doing any kind of treatment or procedure that require multiple daily doses of anesthesia such as this one, I’d definitely suggest contacting the WSU veterinary hospital and ask them if they can tell you what type of anesthesia they’re using for canine radition therapy.
Dr. Ettinger:
My dog, Vicky, was diagnosed with brain cancer (menigioma) in December, 2011. The specialist in Richmond, VA told us about Radiosurgery and regular radiation treatment; he also advised against surgery because it was too risky. I attempted to contact the New York vet hospital that does the radiosurgery and was told that I had to set up an appointment in New York in order to obtain the details. I read the Dog Cancer book and everything else I could find. I did not want to send her away for 17 days of regular radiation at the nearest location (5 hours from home) because she has never been away from home.
Just by chance, I found an article in my local Sunday paper (on the front page of the Daily Press out of Newport News VA) on March 25, 2012 that informed me that the University of Minnesota Vet School was conducting a clinical trial, at no cost to the patient, regarding Canine Brain Tumors. My Vicky had the surgery on April 13, 2012 in Minnesota and the entire tumor was removed. We left Minnesota 48 hours later as a HEALTHY 11 year old Sheltie.
WHY does the Dog Cancer Survival Book NOT MENTION possible clinical trials?
My Vicky’s prognosis was that she would live between 3 weeks and 3 months when she was diagnosed via an MRI on December 12, 2011. I prayed for a miracle, I read everything I could find on Canine Cancer, I changed her diet to the homemade cancer diet in Dr. Dressler’s book, and she was saved by a newspaper article.
I thank the Dog Cancer Survival Book for the diet information – I doubt Vicky would have made it to March 25th had I not followed the diet. However, I could have avoided 4 months of anxiety had the book mentioned the clinical trial that is currently being conducted in Minnesota regarding Canine Brain Cancer wherein they remove as much of the tumor as possible (and have never lost a dog as a result of the surgery/recovery) at NO COST to the patient.
Please mention the clincal trial on your websites/blogs for others with brain cancer.
Thanks for your comments, Patricia, and we are thrilled to hear that your dog is doing so well. The Dog Cancer Survival Guide mentions clinical trials in many places, but most specifically in Part IV, Making Confident Choices. In chapter 24, on page 272, the doctors have a section on Clinical Trials, including some websites that list current trials. Calling local organizations or schools is also a great way to find out about clinical trials, as the doctors point out in that section. Another place they mention clinical trials as a resource is in Chapter 22, on page 261, where they advise you to ask your vet about clinical trials for your dog’s specific diagnosis as one of the hundreds of suggested questions. Many readers have taken advantage of clinical trials, and we’re always glad to reinforce that medicine is always evolving and changing, and new options are always coming in. Of course, it’s impossible to list all of the trials in a book that will be used for years — this information is quickly outdated. This is why the book directs you to places where you can find out about current trials, rather than list the ones current at publication. Thanks for your post!
I would love to explore this with our dog who has an inoperable tumor on his liver. It is on the right side and crushing his vena cava, so there are many complications in removing it with conventional surgery.
Hi Tammy,
Thanks for your question. CyberKnife can be considered for non-surgical liver tumors, but it depends on how close to the vena cava it is and how invasive. We would need a CT to better know. You can contact my Oncology Service if you want more info on CyberKnife. After we have more info (like previous imaging), I can discuss the specifics with our radiation oncologist.
Thanks, Dr Sue