Dr. Michael Kent, a leading expert in veterinary radiation oncology. With a wealth of knowledge and experience, Dr. Kent sheds light on the often-misunderstood world of radiation therapy for pets, particularly in treating cancer.
Join us as we delve into essential questions surrounding radiation therapy—what it is, how it works, and the technology behind it. Dr. Kent explains the intricacies of treating pets, including the importance of quality of life and the various treatment modalities available. He candidly discusses the challenges and triumphs of his work, sharing compelling stories of patients who have benefited from radiation therapy.
Listeners will gain insights into the side effects of radiation, the significance of pet insurance, and the emotional journey that pet owners face when dealing with a cancer diagnosis. This episode is not just for pet owners; it’s a must-listen for anyone interested in the evolving field of veterinary medicine and the compassionate care of our beloved animals.
Tune in for an informative and heartwarming conversation that emphasizes hope and knowledge in the face of adversity in pet health care.
To learn more, check out these links:
UC Davis Weill School of Veterinary Medicine
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All footage is owned by SLA Video Productions.
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Cancer & Quality Of Life For Pets – Dr. Michael Kent
Welcome to Speaking of Pets. I’m Dr. Alice Novotny Jeromin, a board-certified veterinary dermatology specialist.
I’m Janet Novotny King. I’m the doctor’s younger sister. I’m here to help explain more of what the doctors are saying on this show because I’m your average pet owner, lover, and rescuer. Alice is sick of me calling her and screaming hysterically, “What’s wrong?” Here you go. Who do we have on, Alice?
As you know, Janet, when you get the diagnosis of cancer for your pet, it is heart-wrenching. We have a radiation oncologist, Dr. Michael Kent, who is a professor of radiation oncology at the University of California, Davis, which we call UC Davis. Dr. Kent got his master’s degree in Clinical Research. In 2013, he became the Director of the Center of Companion Animal Health.
He’s also the program co-leader for the Comparative Oncology Program at UC Davis Medical School’s NCI-designated Comprehensive Cancer Center. Consequently, he is our go-to person if your dog is diagnosed with cancer and needs radiation therapy. We have several questions for him because we want to know if radiation therapy is the same as it is in us? Is it safer? What tumors does it work for? I’m interested in asking him all this because it’s relatively new.
If you know anything about radiation, even in people, it’s gotten way safer the longer it’s been available. We’re going to welcome Dr. Michael Kent, who is taking time from his busy day to fill us in on all the latest about radiation oncology. Welcome, Dr. Michael Kent. We have so many questions for you. This is an area that I don’t understand that well, and I don’t think pet owners understand that well. We want them to know that this is available for their pet.
Thanks, Alice. Thanks, Janet. I’m excited to talk to you. I’ve tuned in to your show. It’s fun that you invited me.
We’re happy to have you.
We knew he was tuning in.
It’s because we see all of you, readers. Make sure you hold your pets up there so we can see them.
Don’t hold anything else up. We don’t want to see that.
Make sure to comb your hair before tuning in.
Janet always does the flip.
I’m just glad when mine’s not standing up.
Janet, I want to ask a very basic question. What is radiation therapy, Dr. Kent?
Radiation Therapy As A Treatment Modality
Radiation therapy is a treatment modality that we use to treat mostly cancer, but also can be used for some more benign diseases in very specialized circumstances. This is one of our treatment types, just like you might use surgery, chemotherapy, or antibiotics to treat something. We’re using radiation to treat something. With it comes a bit more control over what you have to keep track of, and for safety. Does that make sense?
I like that it’s a therapy. It doesn’t sound as scary. From the human side, when you hear radiation or chemotherapy, it’s scary.
I was thinking back, especially in humans, it seems to have gotten a lot safer over the years. Is it because more knowledge has been gained, Dr. Kent? Why is that?
Call me Michael, please. I’m explaining to students. I had a lecture on clinical radiotherapy for our third years. The name of the game is to get the radiation on the tumor and miss everything else. The technology has changed. I’ve been here 25 years at Davis, from starting my residencies to now being faculty. The advances in radiotherapy have advanced like our computers. Before, when I started here, it used to be a lot of point and shoot and a lot of guessing where things were.
We’ve got such advances in imaging, so I can see things in 3D. In the radiotherapy itself and how we deliver it makes it so that I can almost paint those onto a tumor. If I can hit the tumor and miss normal tissue. That reduces the toxicity. We could chat more about it as you like, but we’re able to reduce a lot of the side effects. That means put more dose on a tumor, which means we could be more effective.
When you have a patient, and let’s pretend it’s a dog. What is the procedure?
There are different ways to think about this, too. There are a couple of different ways. One is that we have to figure out what type of cancer it is. We have to figure out, is it a local disease, or has it spread? It has a tumor. Is it localized in one spot? Is surgery able to be done? If surgery is done, were they not able to remove it all? I always think of cancer. I’m answering a different question. Sorry. Cancer is a local disease, meaning the tumor itself. Cancer is a local, regional disease. Has it spread to the lymph nodes? Is it beyond the local area? Cancer is a distant disease. Has it spread or metastasized to the lungs or other internal organs?
Cancer is either a local disease, a local regional disease, or a disease that has spread beyond. Radiotherapy is something that we use to treat local disease and local regional disease. We can treat the tumor itself. Even if it spreads to the lymph nodes, we can track the lymph nodes now. We can irradiate the lymph nodes to try to get ahead of the cancer. We don’t always succeed, but that’s our goal.
First, often, when a patient presents to me with cancer, it is important to take a holistic approach. What is the tumor type, so I know how it behaves? Is this surgical? Can we remove it with surgery? Least invasive. Is the surgery so invasive that we can’t take it out? The next question is, has it spread? If it’s spread, is it just regionally or is it distant, too?
When a patient presents with cancer, I take a holistic approach: What type of tumor is it and how does it behave? Is surgery possible and minimally invasive—or too extensive to remove? And has it spread locally or to distant sites? Share on XI have a human question. How do you know if it’s spread and it’s not localized in a tumor?
What we do is something called staging. Staging is determining the amount of disease that has spread and where it’s spread. What we do is usually a lot of imaging and a good physical exam. Let’s say I had an oral tumor. I’d be feeling the lymph nodes. The mandibular lymph nodes are what you call them. There are the medial retropharyngeal lymph nodes, which are way up high. I would be checking those. Knowing the type of tumor I have, I know where else it might spread. Maybe I would do a CT scan of the lungs or chest X-rays. Maybe if we’re going to be looking, we’ll do a PET scan, which is a way to look for a functional activity of a tumor. These are ways we can figure out whether this is localized or if it’s spread.
Sometimes, as a radiation oncologist, I always say I wear two hats. I wear my palliation or hospice-type care hat. Where I’m trying to relieve clinical signs and make this patient feel as good as they can for as long as possible, so they can spend time with their family and make it so they can eat. Make it so they can have normal life, and not lame from their bone tumor, so they take away the pain.
I’m doing what’s called curative intent. I’m trying to cure them. Even if I’m not going to cure them, I can get them years. That’s the other goal. How we dose and the type of radiotherapy we do, first and foremost, depends on what that family wants. What can we do? I always say this one when I’m teaching, when I talk to residents, when I talk to students, and even when I talk to owners. Intent is the most important. What are we trying to do to maintain the quality of life, to make sure that your dog, your cat, or your horse has good quality and is living their life to the fullest? Otherwise, what are we doing? What are we in this for?
I love that. Human medicine can take a big lesson from us in veterinary medicine, focusing on quality of life. Michael, are there some cancers that are more responsive to radiation and some that you may use chemotherapy on as opposed to radiation?
If it’s localized, then we’re more likely to use surgery and radiotherapy. If it’s something systemic, like a lymphoma. We’re more likely to use chemotherapy. Sometimes, we will combine radiotherapy with it, but the primary big lifting is going to get done by the chemotherapy. Let’s say we’ve got a mast cell tumor sarcoma. We’re going to try to take it out with surgery. If we can’t, then we’re going to follow up with radiotherapy.
When it comes out with surgery, we’ll look at what it looks like under the microscope and try to figure out how aggressive it’s going to be based on how it looks. If it’s something that’s a higher grade, which is when you look under the microscope and then go, “This looks aggressive or this looks like it’s not so bad.” We may then talk to people about, even after we do local therapy, the risk that some cells may have already broken up and spread that we can’t find yet because they’re microscopic. That’s when you would follow up with chemotherapy because the risk of spread is higher.
It seems to me like these different types of cancers go into different columns.
They do. Certain cancers that are more radioresponsive mean that they die more easily with radiation. Some are harder. For example, a melanoma, which for people is often a skin tumor. It’s associated with getting burns when you’re a kid or sun exposure. With dogs, it’s not. They get them in their mouth. They get mucosal melanomas, which are very similar to those in humans. When you think about it, where does the cancer come from? It comes from melanocytes.
What do they do? They protect you from sunburns. What can they do? They can repair radiation damage from UV radiation. Inherently, they know how to repair radiation damage a little bit. We have to use a little bit higher dose each time we treat to overcome that inherent resistance because they repair DNA well. We have to beat them at their own game in a sense and overcome that.
Alice, I remember when Daddy had cancer. Sandy Markowitz was his oncologist. I said, “I don’t get how this chemo works.” This was in a layman’s explanation. He said, “The chemo will work to a certain point, then the cancer outsmarts it.” It fights back.
Is that true in radiation, Michael, or no?
We do get resistance. It’s not that they become inherently resistant. It’s probably that we didn’t kill them along the way. The cell that was radio-resistant survived. With chemotherapy, I always think of more like evolution and Darwin. You select the cell that survives the treatment. That cell may have made a pump that can pump the chemo out. It learns “to survive” that way. It’s a survival of the fittest cancer cell, which, in case, is not good for us. That cell grows and grows. You have to hit it with another mechanism.
That’s why we do what’s often called multimodality therapy. It’s why we combine therapies. Chemotherapy is not chemotherapy anymore. We have targeted therapies. We have immunotherapies. We have different ways. We try to always hit things from different directions. When you select for these resistant cells, you then use a different mechanism to come in and try to get ahead of the cancer that way.
Anesthesia And Millimeter Accuracy For Treatment Delivery
If I’m bringing my pet in for a treatment, are they put to sleep?
That’s such a bad word. We don’t say it that way.
What do you call it?
Anesthetized or knocked out. We do it under anesthesia. That’s because they can’t move at all. Let’s say I’m treating a brain tumor. I’ve done an MRI. I’ve done a CT scan. I’ve fused the image sets together. I’ve carefully planned. I’m just hitting the tumor, and I’m not hitting normal brain. I put the dog on the table. The machine is rotating around the dog. That makes a lot of noise. They’re not going to stay still. If they don’t stay still, I’d be hitting their brain, their eye, or their mouth. I have to get within a millimeter of where I want to hit.
They’re anesthetized. We make a dental mold that we put their teeth in, and then it goes to a 3D-printed bridge that holds them in place. This way, they don’t move at all. They’re anesthetized. With humans, they tell you to stay very still with kids. They have to sedate them sometimes. Sometimes, we have to position them. They may not be as comfortable. Let’s say we have an old dog, and they have to be on their hips. When my grandma had radiotherapy for breast cancer, I remember her telling me it was so hard for her to lift her arm over her head.
I remember her saying she had trouble shampooing her hair. Her having to lift it so they could access the lift notes is hard on her. In some ways, if we have an old dog, we have to be cognizant of how we’re positioning them, especially when they’re anesthetized. I could put their hips in any direction I want, but then they’ve got to walk after. These are all things we have to be mindful of with an older patient. They’re under a very light plane of anesthesia. It’s safer. They don’t have to be super deep. It’s not surgery. We’re not cutting them.
You don’t feel the radiation. They have to not respond to the machine moving around them and the machine going beep, beep, beep as the radiation comes out. We’re able to keep them light. It’s better to anesthetize them than sedate them, though, because I step out of the room while they’re treated. We keep video cameras on them to monitor them and the anesthesia while the machine is going, but I can’t stay in there while the radiation is being delivered, or I’d be irradiated, too.
This is something that if I have a tube in them and I have IV fluids going, it’s a lot safer. I have monitoring equipment on them. If I have them, they’re heavily sedated. They’re not moving. Let’s say there was a problem. I may not see it as quickly, and I don’t have control of things. Having a light anesthesia is a lot safer to treat them that way. Usually, they’re recovering in most cases, 5 to 10 minutes.
How long is the radiation, a few minutes?
The radiation itself takes a couple of minutes, depending on the plan and the dose. What takes me longer is setting them up. It’s my technical team. I have the best nurses and the best technicians. They’re skilled at helping me set them. We’re setting them up. They’re better than I am. The machine has a CT scanner built in. It’s called a cone beam CT. As it rotates around, we collect a 3D image of the patient, which on the computer screen, I can compare to the one that I did ahead to plan.
We lie them on top of each other, and then I can move the images on top of each other. I can roll it. I can pitch it. I can yaw it, too. I hit boom when I’m happy. It moves the tabletop or the couch that the patient’s on. It’s robotic. It will correct for any small misalignments I have. That’s how we get to millimeter accuracy. I could treat a brain tumor. I can treat a heart-based tumor. We can work on the adrenal glands.
These are all things that have happened because of what we were talking about earlier, the advances in technology and the advances in computers. I’ve always gotten teased that I’m a little bit of a geek or a nerd. I started in engineering school and then found medicine and loved that. This allows me to combine those things. You combine the physics knowledge we have, and combine my ability with computers and everything. I like doing this thing. It’s a puzzle.
I joke to the students that it’s what most people consider boring, but a video game in a sense. We are figuring out how to put the radiation where we want it to go and how to keep it off the organs and tissues. That’s not to say that we can’t avoid all side effects, and we do. We talked to everyone about the potential for that. That’s why we sit down with every owner. We have a nice long conversation about what I can accomplish, what the risks are, because there’s always risk, and what’s the chance of us getting control of this. That’s how I try to approach each of my patients. That’s how my whole service does.
We can’t avoid all side effects, and we make that clear to every client. That’s why we sit down with each owner and have an in-depth conversation about what we can achieve, the risks involved—because there’s always risk—and the likelihood of gaining… Share on XI have a team. I have one other doctor who works with me. We’re hiring a third. I have two residents who work with me. I have four amazing technicians who make it possible to do our work. I couldn’t do it without the nursing skills they have and without the care. They’re monitoring the anesthesia. If I’m doing the radiation, I can’t do both. It’s the shampoo-conditioner thing. You don’t use shampoo and conditioner that’s in one bottle because neither is going to do its job. I don’t use conditioner, but you get the analogy.
You must get to know these patients. What’s the regimen? Daily times three or daily times five?
It’s not just one.
It depends on the goals again. It depends on the type of treatment we’re doing. There are different types. If we’re doing conventionally fractionated, humans will go for six weeks of daily radiotherapy. That’s pretty standard. With dogs, we often do 16 to 20 treatments or fractions. That’s if we’re going with curative intent or if we’re doing something preoperative. In other words, we’re trying to shrink a tumor so that it can then be cut, or if there was surgery already and there’s residual microscopic disease left behind.
If I’m doing something like stereotactic radiosurgery, we’re doing a few doses, usually 3 to 5. We’re trying to ablate a tumor. It’s a gross disease that I can visualize. There are a couple of other specialized things that we look at. It’s not too invasive. There’s no critical normal tissue right there. I can ablate it. I’ll treat it in 3 to 5 with higher doses each treatment. Instead of small doses, many times, I’m doing a few high doses to try to get a similar effect.
What is the most challenging case that you’ve had? No names, but the one that stunned you.
I’ve been doing this for a long time. It’s when you lose. I’m treating a dog now. Its tumor is not doing what it’s supposed to. The dog’s still fine, but it keeps getting ahead of me. We say it didn’t read the textbook. Alice knows that one. We’re doing everything right. They’re doing everything right. It gets ahead of you. We’re still fighting, but those are the toughest cases for me.
What kind of tumor is that, Michael?
It’s an anal gland tumor. The owner found it on their own because they were expressing the anal glands. It was small. Small tumors aren’t supposed to metastasize. We surgically took it out. We were monitoring. We were then following up. We found a freaking 3-millimeter lymph node in the sacrum and a 0.5-centimeter one elsewhere. We surgically went in and took those out just in case. This is months later.
It was just us monitoring. There was a tumor in it. We irradiated the whole chain. That should have fixed it. We’re months out. We went on targeted therapy and now it’s spreading. We just started chemo. This is so tough because it’s not doing what it’s supposed to. Those are the cases that beat me up. That’s why I do research. We’ve got to figure out how to get control of these things. When the cancer doesn’t do what it’s supposed to, it can win. We don’t like that. What are the best things?
I got an email from this woman. She thanked me. I still remember this dog, Tittle. You said no name. Sorry. I treated her dog. Her dog was now getting old and maybe getting a little senile, but I remember I saw her the day before Christmas. She came with her kids, who were young. The dog was obtunded. Alice knows what that means, but to explain it. It means that they’re mentally not there. You have to rouse them to wake them up. Her dog had this pretty big brain tumor.
I got it in two days after Christmas to image because we were closed on Christmas and the day after. I was probably back in Ohio visiting for two days. We got it in, and I treated him. After two years, I lost contact with them because the dog was doing fine. I got this nice email from her thanking me. She sent me some pictures of her dog ten years later. That feels good. That’s the best news. I like that question better, Janet.
I get it. The thing is, you beat the cancer. It worked.
Superficial Tumor Treatments: Brachytherapy And Plesiotherapy
A lot of my patients are geriatric. Cancer hits older people more. Cancer hits older dogs, cats, and horses more. If I can give them their quality of life and the rest of their life, and if I can even hold their cancer at bay, I win.
I know in humans, they do brachytherapy. Is there anything like that in veterinary medicine?
What’s that?
Brachytherapy is where you use a radiation source. You run it through a catheter. You have a robotic machine do that because you can’t stay in the room and move the source. It slowly gives off the radiation. There’s brachytherapy, and then there’s something called Plesiotherapy. That’s where you take a radioactive source of metal. You put it on the surface of the tumor. Brachytherapy is not done as much in veterinary medicine for a couple of reasons.
It’s also used to treat cervical cancer in women, where they have to lie in a hospital bed, and then the applicator is inserted. These aren’t things that we can do in animals as easily. We can’t tell you to lie there for your treatment. The treatment is done over a long-term. It’s in days. There’s a high dose rate, which happens quicker. Even then, you have to put the catheters in and leave them in.
They’re surgically placed. Dogs are going to chew them out. Cats are going to pull them out. That doesn’t work so well. What we do is plesiotherapy. If there’s a superficial tumor, say a white cat has been out in the sun, and it develops a crusty lesion. That’s a big clue. Alice knows this. You’re a dermatologist. What is that?
Squamous cell.
It’s squamous cell carcinoma until proven otherwise. We can be over 90% effective in curing those with a single treatment with strontium-90. We treat a lot of those. We have to anesthetize them. How long it is, depends on your probe. Our probe is on for five minutes and fifteen seconds, with me holding the probe there. I don’t hold it. I use a holder because I don’t want to get radiation. You put it on. That’s going to cure more than 90% of them.
They get them on their noses, eyelid margins, and their ear tips. For ear tips, we will recommend surgery because often, they come back at the edges, but the nasal plenum, or this part of the nose, the little cute pink part on the cats, or on their eyelid margins, it’s quite effective at treating. That’s not an easy place for surgery. The key is, just like people, early detection and treating it early. If it gets too invasive, too deep, the strontium is not going to work because the nice thing about strontium is that it only penetrates 3 millimeters.
That means I can put a huge ablative dose without hurting the underlying tissue. The problem is that it only penetrates 3 millimeters. It was only going 3 millimeters. If anything’s deeper, I’ve missed it. They’re good for the superficial lesions. If your cat’s outside and gets a scab, and it doesn’t heal. It probably wasn’t a cat fight. It’s not a line. It’s not a scratch. Get to your vet. Have them look at it because that’s something we can treat in a single treatment when it’s early.
If it gets late, it’s much harder. I’m going to be telling you it’s 16 or 20 treatments and that I’m not going to cure your cat. I do lots of research as well, and studies, and try to figure out how well things work so I can tell people. In the study we had, our survival after treatment with this was over 2,000 days. The cats do well. Even if it recurs, you stay on top of it. This is something we can usually get control of. It’s early detection, just like people. If we catch it earlier, we can do something about it. If it gets too advanced, it’s much harder.
What can the owners expect to pay?
The first thing I’ll tell you is that anyone out there who’s got a new dog or a new cat, get health insurance, please, because the costs are going up. I don’t know what’s happening with you guys, but the budget’s tough. Even at the vet school, as the state has less money to invest in us, we’ve had to increase our fees. It depends on where the tumor is and what it is. If I need to do a CT scan with contrast, it costs about $2,500 for me to get that.
That’s with the planning. That’s with the anesthesia. That’s with the office call, the blood work, and stuff. If I have to have an MRI also, because it’s a brain tumor, I need to see it better. The MRI is good for mapping brain tumors. I get a merge into the CT at another $2,000. I’m doing strontium. I don’t need to image it. The office call, the biopsy, and the blood work for anesthesia to make sure it’s safe.
We’re probably looking at about $1,200 in that range. If we have an old cat who also has a heart murmur and is sick otherwise, and things like that, it’s going to add more money. We have to make sure it’s safe first and foremost. Always think, “Do no harm.” If I’m doing a palliative course of radiation, that’s my hospice care hat. It’s going to be another $4,000 or $5,000.
How many radiation oncologists are there in the country?
Worldwide, I believe there are about 150 of us. Europe has set up its boards and has set up as a new specialty in the last couple of years. Most of them are in the United States. There are a few in Asia. There are probably 125 in the US.
I’m assuming they’re probably at teaching hospitals like Davis, Cornell, and Ohio State.
Equipment Costs And The Importance Of Pet Health Insurance
All those places, yes. They are also in private practice. There are more in private practice. There are three other places right near me in Northern California where I am. Pets have become more part of the family and people demand better healthcare. That’s there. I do want to finish answering your question, though, because when we’re getting up to either stereotactic radiosurgery or we’re getting up to fractionated, it can be $10,000 or $12,000 more. It’s expensive.
That’s because machines are several million dollars. Service contracts are going to be $250,000 a year. Your physics bill is going to be $50,000 or $100,000 a year. It starts adding up very quickly. In human medicine, there is insurance, and Medicare helps pay for this. Again, most people are in Medicare or Medicaid as they get older. The government helps pay for that. I’m all for healthcare. That’s okay. It’s a good use of my tax money.
I’m happy to pay and I’ll pay more. I always say, “If you want to be a patriot, pay your taxes.” Put your money where your mouth is. I am so glad they were there when my grandma needed them. It didn’t break my family for her to get treated. That’s why we have it. That’s why I like to say, please get health insurance for your dog or your cat.
If you love this cat, not any cat, get health insurance. I could pay $1,000. I could pay $2,000 or $3,000, but you start getting up to $5,000, $10,000, or $20,000. If you have surgery, too, that’s hard. It’s going to hurt. I’d rather pay each year, pay into this, and get a good health insurance plan for my dog or my cat. That way, I’m making decisions about quality of life. I’m not making decisions about whether I can afford this or not because it is too expensive. It is a hard decision.
As pets have become more and more parts of our lives, we see a lot of elderly people that are empty nesters. These are now their family and their kids that they see every day, who help them with everything. This is important. We keep them together. I became an oncologist, not because I studied cancer. It was during my internship at Penn. I went through my oncology rotation. The people who wanted to treat cancer were the best owners.
As pets become an increasingly central part of our lives, many elderly empty nesters now see them as family—the ones they care for daily and rely on for companionship and support. Share on XI’m like, “I need to work with these people, these dogs, and these cats.” That’s when I said, “I need to learn more about cancer,” so I switched up. I was thinking of either emergency critical care or endocrinology. I was thinking this is what I want to do. I met these people in emergency critical care. I went, “I’m going to follow these people up long-term.” You don’t follow them up long-term. They come to your emergency room. You treat them.
You either transfer them to someone else to treat them, or they go home. I wanted that long-term relationship with people. That’s where I fell in love with oncology first. I learned to hate cancer and figure out how to treat it. I switched up what I wanted to do because it’s the best people who are bonded. It’s the best animals that they’re bonded to. I self-selected to help the best people.
You could have gone into dermatology, Michael, because that’s long-term relationships, too. Allergy is forever. Let me tell you.
I have had allergies forever, too. You probably hear a little bit of it.
You’re supposed to outgrow yours as a human.
Mine have only gotten worse. We’re hitting spring here. It’s the end of winter.
Janet, your allergies were bad when you lived in California.
It was the Acacia, that yellow thing, for two weeks. It’s because I didn’t grow up with it. We moved to California. I remember I went to the allergist. He’s like, “Where’d you grow up?” I’m like, “Ohio.” He goes, “You didn’t have this.” Two weeks out of every year was that Acacia. My husband was allergic to California grasses.
I’m allergic to everything. I could have gotten into dermatology for that. I chose cancer for whatever reason. Maybe I didn’t have a dermatology rotation in my internship. That might be it. I found cancer, and I said, “This is what I want to do.”
Correct me if I’m wrong, but there’s more geeky engineering in oncology.
I took the long circuitous route. I did a medical oncology residency first because I didn’t know about radiation. I went and did the Rad Onc residency after. I have a secret for you. If you stay at the University of California long enough, they eventually start paying you. I did two residencies in my master’s here, and I was threatened with divorce if I did a PhD.
Is that right?
Not seriously, but it was like, “You need to start making some money because we’ve got to pay a house off, and you have student loans.” I stayed on after my residencies. I still need to know about cancer in general. It was time well spent. The first residency and doing radiation on top of it helped make me a better clinician and more well-rounded.
Michael, when our younger son was applying to college and to the UC system. He went, “Mom, come here.” It’s this whole form on the computer. “Did anyone in your family, your direct descendants, serve in the Vietnam War?” There are questions like, “Are you of native American?” He finally goes, “I can check a box.” I’m like, “What?” “Were you born in the State of California?” He was. He was born in Palo Alto. We got to check a box. He still didn’t get in, but that was my UC experience.
Out of state, though, is harder because it’s heavily subsidized by the state. That’s a whole other topic. If you want to talk about that, I’m always happy to because it’s so important. The student debt loads are high. We’ve done a lot to counteract that, but still, it’s tough. Especially in today’s world with a lot of uncertainty and funding at universities coming under attack. It’s scary.
Have you ever done any radiation on any exotics? Do people from the zoo call you and say, “We have a tiger with a melanoma?”
What do you do, put the snake down?
I have treated a snake before. We treated fish before. We had a tiger once.
What kind of tumor did the tiger have?
Sarcoma.
What about the fish? How do you keep that thing alive?
They get tumors, Janet.
Do you do it underwater?
You flow the anesthesia in the water over them. We can put them under the linear accelerator. I don’t do the anesthesia regardless. We have anesthesiologists. I already told you about my fabulous techs, who do it as well. We have a whole group for avian exotics and fish medicine. They can anesthetize them quite well.
What did the snake have? What type of tumor? Was that a sarcoma also?
It’s a skin cell carcinoma on the skin. I’ve treated another one. I’ve treated a few over the years. They’ve had different types of tumors. They get different types as well, but skin tumors are what we’ve done most. I treated a penguin with a melanoma before. There are lots of different types. It was at the zoo. It was so cute.
Look at their little feet.
It was so sweet.
Is your equipment the same as what they use on humans?
We use a linear accelerator. Ours is made by Varian. There are a few linear accelerator makers in the world. We use the same treatment planning software like we use the same CTs and MRIs. They don’t make a special horse linear accelerator. They don’t make a special dog linear accelerator.
The sizes can make it tricky. Trying to get a horse in, they don’t go on the same table, but we have them on a special table. We have a couple of people to help push them in and use different anesthesia. It can get tricky, but it’s also fun. The variation is also what’s cool. It’s the same equipment. That also makes it more expensive. I’m buying a linear accelerator. That’s the same one. The best equipment available for humans is what we use because it’s important. That’s how we get the best results.
The servicing of it has to be expensive, too.
I already mentioned a bit about what our service contract runs, but it’s important. It’s old technology. I used to joke that our linear accelerators were as complex as the space shuttle. All the main linear accelerators that are used are made. Do you know where, Janet?
It’s in Stanford.
It’s in Palo Alto.
I lived adjacent to the SLAC, the Stanford Linear Accelerator.
That’s a giant linear accelerator.
It’s a mile long.
That’s not the medical ones. That’s the ones that do molecular.
My husband was an engineer. We first moved there. I found out you could do a tour of it. He was so jacked up about going to the SLAC, the Stanford Linear Accelerator. We used to drive right over it.
The medical ones are also built there. They’re by Varian Corporation. It’s a pretty cool facility. Things have changed over the years.
It’s so cool. We have to ask you the guest question. What is your pet or human peeve?
My pet peeve is unkind people.
That’s a good one.
I will tell you what I’ve learned. When people come in upset, it’s different than unkind. It’s a long time to learn that. The other thing is no lying. It’s unacceptable. Those are the two things. You have to be kind, and you can’t lie. You can fix anything or at least work with it.
Unkind has an edge to it.
Sometimes, people think, “If I come in yelling, I’ll get what I want.” Usually, I can talk with them and let them understand that they’re not helping. They’re making it harder for everyone to help them. I’ve not come across unkind people in my work. I come across people under severe stress. They’re grieving already. That’s different than general unkindness. That and lying are the two things that are my unacceptable lines.
Anytime someone hears the C word, the cancer word, it’s terrifying.
It’s so emotional.
It’s something that’s out of control.
I understand. A lot of times at my first consult, I think they hear, “Cancer, blah, blah, blah, cancer,” and so we write everything out for them. We’ll take time to talk to them again because it’s so hard to listen while you’ve got this fear going on. This is tough. It’s a scary diagnosis, even if we can have a good chance of getting a good outcome. Cancer is tough, and cancer kills. We still need to make great strides. Did you know it was Nixon who started the war on cancer?
Cancer is tough, and it can be deadly. We still need to make great strides. Share on XNo.
It’s the National Cancer Institute, National Institute of Health.
I did not know that.
The best thing he did as president was to start the war on cancer.
I didn’t know that.
It’s so important that we continue research because we’ve changed cancer from universally deadly in the 1970s. We talk about five and ten-year survivals now in people and dogs. Half of dogs over ten are going to die of cancer. A quarter of cats are going to get cancer. More than a quarter of us are going to get cancer. Up to half of humans are going to get it. We still have to tackle this. We still need the National Cancer Institute. We still need the NIH because otherwise, we would have given up. We can’t surrender the war on cancer. That would be cowardly.
I have one more question. What are the side effects of radiation? What can you expect when you’re at your pet’s recovery?
Acute And Late Side Effects Of Radiation Treatment
That’s a good question. You know that because you’re a smart person. That’s what people ask me first. We break effects into what we call acute effects and late effects. Mostly, the side effects we see are going to happen in the area we irradiate. They are right where we treat. If I’m treating a brain tumor, you’re not getting radiation sickness and vomiting. That’s not there. It’s different than a whole-body exposure from an accident. This isn’t Chornobyl. This isn’t Hiroshima. This isn’t those kinds of things. This is a very controlled dosing.
We prescribe a dose of radiation like you would give a milligram of drugs. We give a gray of radiation. The area that we treat is where it’s going to happen. If you have a skin tumor, I’m going to get some skin reaction. It’s either dry or moist desquamation. Think of if you had a wound that was moist, and it’ll take a few weeks to heal up. If we’re doing conventional fractionated, we’ll start to see some of the signs the last week of radiotherapy and even more the week after we finish. They’ll take a couple of weeks to heal.
You’re also going to lose hair just in that area. The dog or cat doesn’t lose all their hair, just that one local area. Usually, we’ve shaved it to see the scar anyway and line up the machine. The hair will grow back. It usually takes about six months. It grows back thinner and grows back gray or white. If we’re treating in the mouth or somewhere there, I tell people it’s called mucositis. I explain it as thinking of the day after eating hot pizza and having a pizza burn. We can manage things with some pain medication. The mouth heals quickly, also.
There are other things, too, that we worry about. Radiation can be used to treat cancer, but it can also cause cancer. There’s about a 1% risk long-term. Same for you or me, if we had radiotherapy, two years, five years down the road, or more, your pet could develop cancer where I treated them. It’s a different type of cancer. This isn’t a recurrence. This is a new type of cancer because of the treatment I did. The risk is 1% or so, but this is part of informed consent because the owners or the parents have to make the decisions for the pets. They have to understand the risks.
There are other side effects we see, but they’re so related to where that particular tumor is and what the treatments are. The acute ones, we dose, so they’re manageable. We treat them so they’re manageable. That’s something we always talk to every owner about, what the risks and benefits are. You have to be careful if you’ve had radiation in your mouth. Dental work later, you have to be careful. That’s where we work with the local vets.
If someone pulls a tooth traumatically, that can actually cause the bone to break because the bone doesn’t heal as well after. The big word for that is osteoradionecrosis. That’s something we never want to see. It’s educating the owners and then talking with their local vets, too, so that they know what we’ve done. They know what’s safe and not. If you need dental work, we say, “Go to a dentist. Get it taken care of that way, so we can avoid a problem down the road.”
What you do is amazing.
What you do is pretty cool. I like that, too.
We can’t thank you enough. I went into this knowing a little bit about radiation oncology, but it’s so encouraging.
It’s comforting.
It gives quality of life to our pets. I love that, quality of life.
That’s what I’m in it for. Thank you. It’s so important that we have options and choices. With a cancer diagnosis, you feel like all those things are taken away. It’s so important that you at least find out what you can do so you can make the best decisions. I tell this to people all the time. There’s no good choice. You have multiple bad choices. What’s right for you and your dog, your cat, or your other animal, it’s always playing odds. What we try to do is make this as manageable as possible.
There are no good choices—only difficult ones. What’s right for you and your dog, cat, or other animal is always a matter of weighing odds. Our goal is to make that process as manageable as possible. Share on XGet pet insurance.
I’m doing an ad for them.
We did have a pet insurance guest.
It’s the Pet Insurance Institute. She reviews all the different pet insurance plans. It was very helpful.
I’m going to tune in to that episode, too.
It was good. It was Dr. Frances Wilkerson.
Thank you, Dr. Kent.
You’re welcome. My dog and my two cats, you know what they have?
It’s pet insurance.
Exactly.
I knew that.
I want to thank you both for taking the time to speak with me and for inviting me on. I feel like I’m getting a little celebrityhood here. I appreciate it because it’s so important. The topic affects so many of us. It’s great what you’re doing to be able to provide people with information. It’s fun to talk to you. Alice, it’s been years since I saw you in person. Janet, I have never met you before. This is great.
I’ll meet you on the Tappan Zee next time you’re out.
Janet, we’d better wrap it up.
We’ve got to wrap it up.
I want to talk to you longer.
You can come back. We love that.
We’re going to have you and Dr. Karl Jandrey together like a sumo match. Talk about the emergency radiation.
We could do doctor talk.
I love it.
This is Dr. Alice Novotny Jeromin, wrapping it up.
This is Janet Novotny King, saying thank you for joining us, Dr. Kent. We’re so pleased you’re on. It brings patients a lot of comfort. They’re big decisions to make when your pet has cancer. Thank you for the passionate work that you do.
Thank you. Not jokingly, it’s an important topic. Thank you for asking me.
Important Links
About Dr. Michael Kent
Michael Kent is a Professor of Radiation Oncology in the Department of Surgical and Radiological Sciences at the University of California, Davis, School of Veterinary Medicine. Dr. Kent graduated from veterinary school at UC Davis in 1997. He then went on to do a rotating small animal internship at the University of Pennsylvania. This was followed by a year in private practice in Pennsylvania before going on to do residencies in Medical and Radiation Oncology at UC Davis, where he also received his Master’s Degree in clinical research. In 2013, he became the Director of the Center for Companion Animal Health. He is also the program co-leader for the Comparative Oncology Program at the UC Davis Medical School’s NCI-designated Comprehensive Cancer Center. He is an author on over 125 peer-reviewed publications. His main research interests include clinical outcomes for veterinary patients receiving radiotherapy and optimizing radioimmunotherapy. For a listing of published works, please see: http://www.ncbi.nlm.nih.gov/sites/myncbi/michael.kent.2/bibliography/47869227/public/?sort=date&direction=ascending