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Early Dog Cancer Warning Signs

Early Dog Cancer Warning Signs | Dr. David Vail


Does your dog seem off? Trust your gut, says oncologist Dr. David Vail. Whether it’s cancer or something else, early detection improves outcomes.

Episode Notes

There are very few signs that directly indicate your dog has cancer. Even a lump could be an infection or a benign growth. Many common early signs, such as lethargy, weight loss, vomiting, or increased drinking, can be caused by a variety of health problems.

Veterinary oncologist David Vail recommends keeping up with regular veterinary exams and going in whenever your dog doesn’t seem right. Your vet can do testing to narrow down the possible issues that could be causing your dog’s symptoms, and track the size of any lumps so that you will both know if a lump starts to grow at an increased rate.

Listen in for more signs that can indicate early cancer, as well as tips on how to decide if a test is worth running.

Related Links:

What Are the Symptoms of Dog Cancer? podcast episode

Checking Your Dog’s Symptoms on the Internet? Here’s What You Need to Know podcast episode


0:00 Start

2:13 Lumps

5:00 Clinical Signs

6:49 Trust Your Gut

12:27 Liquid Biopsy

18:00 Regular Exams

About Today’s Guest, Dr. David Vail:

Dr. Vail received his DVM from the University of Saskatchewan in 1984 and subsequently completed an internship in small animal medicine and surgery at Colorado State University prior to practicing in his native western Canada for two years. He followed up with a residency in Medical Oncology at the Animal Cancer Center at Colorado State University, completed in 1990. He is currently Professor and Barbara A. Suran Chair in Comparative Oncology at the University of Wisconsin-Madison and the UW Carbone Comprehensive Cancer Center. Dr. Vail has published over 170 peer-reviewed scientific manuscripts and 50 book chapters in the field of veterinary and comparative oncology. David is co-editor of the textbook Small Animal Clinical Oncology (6th Ed). In the past he has served as President of the Veterinary Cancer Society and the Canine Comparative Oncology and Genomics Consortium (CCOGC), Chairman of the Scientific Advisory Boards for both the Morris Animal Foundation and the American College of Veterinary Internal Medicine Foundation, is a founding member of the Comparative Oncology Trials Consortium (COTC) and past North American Journal Editor for Veterinary and Comparative Oncology. He has been honored as the recipient of both the Mark L. Morris Sr. Distinguished Research Award and the Pfizer Award for Veterinary Research Excellence.

Other Links:

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Dog Cancer Answers is a Maui Media production in association with Dog Podcast Network

This episode is sponsored by the best-selling animal health book The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity by Dr. Demian Dressler and Dr. Susan Ettinger. Available everywhere fine books are sold.

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[00:00:00] >> Dr. David Vail: Really nothing is as good as having routine veterinary care – as they get older and are slowing down, a perhaps twice a year physical exam by a veterinarian – because that’s where a lot of the early signs can be picked up.

[00:00:19] >> Announcer: Welcome to Dog Cancer Answers, where we help you help your dog with cancer.

[00:00:25] >> Molly Jacobson: Hello, friend. As you know, the best chance we have of treating canine cancer is if we catch it early on. So what are the signs we should be looking for? To answer that question, we are joined by Dr. David Vail, a veterinarian oncologist from the University of Wisconsin. Dr. Vail, thank you for joining us today.

[00:00:46] >> Dr. David Vail: Thanks for having me here. It’s my pleasure.

[00:00:48] >> Molly Jacobson: It’s such a pleasure to have you join us. So I’ve heard that the five most dangerous words in the English language are, "Maybe it will go "away," or "Let’s see if it grows." And I believe you said that.

[00:01:02] >> Dr. David Vail: Yeah, probably somebody said it long before me, one of my mentors, um, probably said it first, so it’s out there in the vernacular. But it is very true. You know, most of, and you know, the classic – we were talking about the signs of cancer, the classic sign of course that comes to mind when we think of that is, "I found a lump or a bump."

And in those scenarios, the good news is that the vast majority of lumps or bumps that a caregiver will find are benign disease and can be dealt with good outcomes. So that should be the first thought is that, you know, this is something that I can deal with. But it really behooves us to make sure that that’s the case and to find out what it is and deal with it.

The other piece of information that’s so important to know is that even if it is bad disease, the earlier that we catch it, the more likely there will be a curative modality or treatment that can be applied before, for example, with cancer, before it’s spread to the local lymph node or, or beyond, or before it’s gotten so large that a simple surgery or simple radiation therapy will not be able to deal with it.

So you wanna know whether you can ignore it. That’s what I always tell my, my clients and my students that, uh, don’t ignore anything until you feel comfortable that you can ignore it. And even then, we don’t ignore it. So again, that classic lump or bump, what we always do is measure it. And in today’s world, of course, take a picture of it, and usually we’ll have a picture with a ruler or a set of calipers with it so that we know the size of it. And then do some type of screening test with it, and then put that right in the, the problem list in the medical record, whether it be electronic or written, with the date, the photo if it’s there, and the size because you may not be the same veterinarian, you may be in a busy practice that has plenty of associates, and you wanna know whether things are changing.

So if I, for example, the, the classic screening test for a lump or a bump that is found is something called a fine needle aspirate. We put a tiny needle in, we draw some cells and have a look at it, and the vast majority of things, for example, in an older dog, the classic would be a lipoma, benign fatty mass.

So in that scenario, I’m not going to ignore it. I’m gonna have it right in the face page of my medical record, something called the master problem list, and it’ll say, On June 18th, I found a lump that was three centimeters in longest diameter, an aspirate showed that it was a lipoma. So I’m not ignoring it.

I am documenting it. And the next time I see that patient, if it’s changed, then I’ll go, maybe I should put another needle in this, or maybe I should be concerned. So yeah, it’s really important to not just, maybe it’ll go away or let’s see if it grows, is to ignore it if it’s appropriate to ignore it and don’t ignore it if it’s not.

[00:04:00] >> Molly Jacobson: So if my dog gets a lump, how soon should I go to the vet to make sure that they’re able to look at it?

[00:04:07] >> Dr. David Vail: Generally from an oncologist standpoint, and of course in my practice, you know, I see, you know, the, the good, the bad, and the ugly. So I will always say that, you know, the earliest something new is investigated, the better. Because the earlier we find disease, the much more likely it is that it’ll be something that we can apply a curative intent therapy to. So yeah, within reason, the earlier the better.

[00:04:32] >> Molly Jacobson: The earlier, the better. Okay. Are there any other early warning signs that cancer is in process?

[00:04:40] >> Dr. David Vail: Certainly. And so, you know, as I’ve said, the one that clearly comes into everybody’s mind initially is that, oh, I, I feel a lump or a bump, or my groomer has felt a lump or a bump, and they discuss that with you. That’s kind of the classic. The others, and you know, there’s all kinds of lists out there, there’s the eight most common, the 10 most common, the 12, whatever.

[00:04:59] >> Molly Jacobson: Right.

[00:05:00] >> Dr. David Vail: Those other clinical signs or symptoms tend to be much less specific, that is, that they’re by no means classic for cancer. They’re general symptoms that could be due to cancer, but there are many other diseases. So they’re ones to say, I have this clinical symptom, therefore it should be investigated. That’s all. It’s not, I have this, this symptom, so it is cancer. But the others that we always talk about are, you know, abnormal odors, something new, either from the the ears or any other body cavity, or the mouth in particular.

All of a sudden bad breath in an older dog should be of concern. A non-healing wound, or sores that come up, those certainly should be investigated. Loss of appetite or loss of weight, those are very non-specific signs. There are literally dozens of diseases that will cause weight loss, and by no means is that a classic for cancer, but it’s a sign that should be investigated. Coughing or difficulty breathing, of course, the difficulty breathing, you know, depending on the severity, could be an emergency and obviously needs to be looked at.

But those could potentially be an early sign of cancer. Increased drinking or increased urination, change in bowel movements. Certainly, any blood in the bowel movement could be an early warning sign. Again, not specific for cancer. Evidence of pain, a lameness that comes up all of a sudden, uh, especially in an older dog that doesn’t have a history of some traumatic event. Even something as simple or as non-specific as lower energy levels. That could be an early sign of cancer, but again, is by no means classic for cancer.

So kind of the bottom line is, most of our caregivers are in tune with their companions, and they know when something is different or odd or not part of their normal daily routine. And if it’s consistent and troubling, then it should be investigated, not just from a cancer standpoint, but from a general quality of life and medicine standpoint.

[00:07:13] >> Molly Jacobson: Yeah, that makes sense. So we know if something’s not right, we should get it checked out, and trust our gut, it sounds like you’re saying.

[00:07:22] >> Dr. David Vail: Exactly.

[00:07:23] >> Molly Jacobson: Uh, do veterinarians trust our gut? Does that matter to you?

[00:07:26] >> Dr. David Vail: Yeah. You know, there’s certain intuition that really comes with experience as well. So an early, a veterinarian that’s very early in their career should trust their gut less than a veterinarian like myself who’s been practicing for 32 years. But there is a flip side to that, that you know, you can get, uh, somewhat cavalier and over confident in your intuition, and you should always back it up with science as well.

[00:07:54] >> Molly Jacobson: Right. Get it checked out.

[00:07:55] >> Dr. David Vail: Yeah.

[00:07:56] >> Molly Jacobson: And so what I heard you just say, and I just wanna make sure I got it, because you’re saying lumps sometimes are cancer, sometimes are not.

[00:08:05] >> Dr. David Vail: Right.

[00:08:06] >> Molly Jacobson: But so are lots of other things-

[00:08:08] >> Dr. David Vail: Absolutely.

[00:08:08] >> Molly Jacobson: -that could come up. But just because your dog is extra tired or is not eating lately does not mean they have cancer. You don’t have to jump to that. It could be other things.

[00:08:19] >> Dr. David Vail: Yes. You certainly don’t have to jump to that. That would be on, you know, what we call our list of differential diagnoses. So, there’s a list of – based on the symptom that’s there, we would come up with, you know, a list of potential diseases that could be causing that symptom. And, uh, it depends on how specific that symptom is. If it’s something like lower energy levels, there’s literally a hundred things on that list. If there’s something like bleeding from the nose, there might be five things on that list that we would wanna rule in or rule out.

[00:08:52] >> Molly Jacobson: Okay.

[00:08:53] >> Dr. David Vail: So it really depends on how non-specific that clinical symptom is.

[00:08:58] >> Molly Jacobson: So, a lot of times people wonder, should I go to the emergency? Like they’re very upset, right, because they know their dog isn’t well and they get very upset about it, and they think, should I just go to the emergency or should I wait until tomorrow or the day after, or a week later when my regular vet can see my dog?

[00:09:17] >> Dr. David Vail: Right. Yeah. And that, that again plays into the caregiver and their understanding of their particular companion. So if it’s something obvious like breathing difficulty, that’s obvious, you should seek, uh, medical attention immediately. So an emergency facility or an urgent care facility would be appropriate for something like that.

One vomiting event in an otherwise healthy and happy dog is not something that I would generally say, go to a, an emergency room. I would, you know, in a situation like that, say withhold food for a few hours, watch your pet closer than you normally would, make sure that they’re bright and alert and responsive at that point.

If they start to have, uh, more vomiting over a period of, a shorter period of time and become lethargic or, or lower energy level, maybe they’re becoming dehydrated, then that would become more and more urgent. So it would depend on the type of symptom and how urgent it appears and how affected in general your companion is.

So again, a one time, you know, for example, with the cats that I’ve owned in my life, if I went to the emergency room every time one of my cats vomited, I would spend my entire life in the emergency room. So, yeah.

[00:10:35] >> Molly Jacobson: Very true. I think that’s the balancing act, right?

[00:10:38] >> Dr. David Vail: Right.

[00:10:38] >> Molly Jacobson: It’s like, right. Yes.

[00:10:40] >> Dr. David Vail: Now if you are unsure, it’s always better to err on the side of, I better call somebody and bounce it off somebody that has more experience. So most emergency hospitals, eh, if your general practitioner’s closed, will triage over the phone to the best of their abilities, bearing in mind that the information that you give is all the information that they’ll have, they’re not seeing your, your companion. So you wanna be thorough with your discussion and your concerns.

And if you’re not happy with the response, state that, in a nice way, and say, look, I hear you, but I know my companion and, and he or she is really acting depressed, and, and I would really feel more comfortable being seen. Then it’s, you absolutely have the right to override that and say, look, I’m coming in, I just don’t feel comfortable.

At the end of the day, as I’ve said, uh, before, and I always teach that, uh, the caregiver is the best judge of their animal’s quality of life. And, uh, uh, listen to them because they see that that companion in the natural environment. Whereas we as veterinarians, we see them in an unusual environment in hospital, they’re stressed. They’re like kids.

You go to the pediatrician, my kids always got better as soon as they walked into the door because of stress or whatever. They’re always, their symptoms go away and you’re standing there going, well really, he was doing this before, right?

[00:12:10] >> Molly Jacobson: The adrenaline kicks in.

[00:12:11] >> Dr. David Vail: Absolutely. Yeah.

[00:12:12] >> Molly Jacobson: And adrenaline is a miracle.

[00:12:14] >> Dr. David Vail: It can be.

[00:12:15] >> Molly Jacobson: Yeah.

[00:12:15] >> Dr. David Vail: Yeah.

[00:12:17] >> Molly Jacobson: Okay. Hold that thought while we take a short break to hear from our sponsors and we’ll be right back with Dr. David Vail.

And we’re back with Dr. David Vail. So I wanted to ask you, you know, we have new early detection strategies entering the market. Some are covered by pet health insurance, others aren’t, some are covered in some circumstances. What do you think of some of these new early detection tools like the liquid biopsy test?

[00:12:49] >> Dr. David Vail: Yeah, so, and there is a lot of that currently coming into the market. And there is no perfect pre-screening test at this point. Even on the human side, physician based medicine, the scrutiny to get an early recognition test on the human side is much stricter. It requires FDA approval and very, very good documentation.

This is all relatively new to the regulatory organizations of the government on the veterinary side, and the bar the, the science bar is, is quite a bit lower. And it’s a little bit like the wild, wild west right now. So there are a lot of tests coming onto the market, they have some pros and they have some definite cons, and I definitely would not make a, a life changing decision based on those early tests.

Many of them are just being developed and we’re just applying a longer term data, collecting data on those tests as to what does it mean. I always say if I have a test, I wanna have an actionable result. That is that if I get a a positive test, is there something I can do based on that positive test? And if there isn’t, then I don’t wanna know about it. I don’t want that test.

[00:14:15] >> Molly Jacobson: Right.

[00:14:15] >> Dr. David Vail: The kind of, the classic example on the human side is, uh, prostate specific antigen. And every male over the age of 50 is asked by their physician whether they want a PSA test. And most generalists, general practitioners, will tell that male human that this is a very controversial test now because a lot of people will develop a high PSA and never have a problem with their prostate, and in lesser times, five, even 10 years ago, people were undergoing very aggressive therapy when they didn’t need to.

And so that’s a screening test and it’s a very inadequate screening test. So a lot of people, and personally, I chose not to get the PSA test because it really doesn’t have an actionable result in many cases. Now, the caveat to that is if you do have prostate cancer, or you have some other cancer that there is a screening test, whether you’re a dog or a cat or a person, and the screening test – really, the place for a lot of those screening tests is, if before treatment that test is very positive, and after treatment it’s very lower or nonexistent, then that test becomes much more helpful to determine whether the disease is recurring or responding to treatment or not.

That’s kind of where we are right now in the veterinary world, rather than having any good screening test for who has cancer and who doesn’t. That test is currently not available that’s specific or sensitive enough in veterinary medicine to start applying now.

[00:15:53] >> Molly Jacobson: Okay. So if somebody is interested in trying one of these new tests and seeing what they get, results, they’re contributing to knowledge in general.

[00:16:04] >> Dr. David Vail: Exactly. The way I present it to my clients now is, yes, we can run that test and that’ll get into the database for the future, but I wouldn’t make any life altering decisions based on that test. It might tell me to do more testing.

[00:16:17] >> Molly Jacobson: Right. So we don’t have anything right now – we don’t have a blood test, for example, that would say, oh, you have cancer. We have a blood test that would say, Hey, there’s something going on that’s unusual and maybe you should investigate it further.

[00:16:31] >> Dr. David Vail: That’s correct. That’s to the best of the, of what we have currently now.

[00:16:35] >> Molly Jacobson: Great. Are there any exciting new things coming up?

[00:16:40] >> Dr. David Vail: Yeah, no, I mean there are vari-, various types of, you know, and the, the idea of having a liquid biopsy – the key to liquid biopsies right now, or the holy grail, is to have a, a simple blood test that will tell you very early that you have cancer in a very early stage that can be dealt with.

[00:17:01] >> Molly Jacobson: Right. That would be the ideal, right? That’s what we’re hoping for.

[00:17:04] >> Dr. David Vail: And the the types of liquid biopsies that are currently available, the sensitivity for them right now is still suspect. And until we know a lot more – for example, some of the tests that are currently available will give you a, something as short as a five week lead time before you would’ve diagnosed it anyways. Now is five weeks an actionable period of time to know? Maybe, but not likely.

So we’re talking about tests that could diagnose cancer before, when it’s still a single cell or, or a few thousand, or a few million cells before it, it, uh, grows into an actual tumor. Those are the kinds of tests that, um, there are some tests like that, that are in early development, both in the human oncology world and the veterinary oncology world, we’re just not quite there yet.

[00:18:00] >> Molly Jacobson: Okay. All right. Are there any other early detection strategies that we haven’t talked about already that you think might be helpful for people to keep in mind?

[00:18:12] >> Dr. David Vail: Yeah, I think, uh, just getting back to our basic discussion of what are potential warning signs of cancer and acting on them early, and really nothing is as good as having routine veterinary care. So at least, especially in companion animals, dogs and cats, dogs that get above the age of six should have a, at least an annual, and as they get older and are slowing down, a perhaps twice a year physical exam by a veterinarian because that’s where a lot of the early signs can be picked up. Just some basic blood tests looking for basic organ function, you know, having a, a trained set of hands do a, a good physical exam and palpation and rectal exam, and listen to the chest, and listen to the heart, and find these signs early rather than later. And so good, preventative care and, uh, annual checkups, uh, very important.

[00:19:10] >> Molly Jacobson: That seems like really solid advice. Are there any imaging tests that you think people should be doing routinely as dogs get older, in those wellness exams?

[00:19:20] >> Dr. David Vail: Yeah, so there are certainly routine imaging or diagnostics that are used on the human side. I mean, the classic example would be colonoscopy for colon cancer. Right? Thankfully, the incidence of colon cancer is extremely low in dogs, so that’s not something that we would routinely recommend. In people, mammographies for breast cancer very early, for women at risk earlier than women that don’t have risk factors, certainly the, it’s kind of a moving target, but anywhere from 40 to 50 years of age.

Because our dog population, at least in North America, is primarily a neutered or a spayed population, the risk of breast cancer is extremely low, mammary cancer in dogs. So we don’t really recommend routine imaging in that case. I have patients, or I have caregivers that come to me and say, look, I want an annual CAT scan for my dog every year.

And you know, and I’ll look him in the eye and say, Look, the, the cost benefit of doing that just isn’t established in the dog. Yeah, we can do it. No diagnostic test, or virtually no diagnostic test, is without risk. CT scans do increase, very small, but um, over time could build up, uh, radiation exposure, for example. As the newer machines come along, the radiation exposure gets less and less over time.

And again, the ability to say, is this test have cost benefit, that is that, are you going to pick up something that you could deal with early, hasn’t been established for something like whole body CT, even on the human side. For some things like uh, lung cancer, there are now newer regulations in people coming out – not regulations, guidelines, that it might be appropriate, especially in people at risk, for example smokers, to have a chest radiograph or a chest CT performed after the age of, you know, et cetera, et cetera.

But really nothing like that is established in, in veterinary medicine at this point. Thankfully, our dogs are not smokers, our cats are not smokers, although they are exposed to secondhand smoke, et cetera. So.

[00:21:28] >> Molly Jacobson: Right. Right. Well, thank you so much for joining us today. It’s been very helpful.

[00:21:34] >> Dr. David Vail: Again, my pleasure. You know, anything we can do to educate ourselves and, you know, I’m a caregiver of companion animals as well, and so, uh, anything I can do to enhance early detection and enhance the quality and quantity of our companions’, uh, lifespan, I’m certainly on board for.

[00:21:53] >> Molly Jacobson: Well, thank you, and I hope you’ll join us again if we have more interesting questions to ask.

[00:21:58] >> Dr. David Vail: Yeah, absolutely. Anytime.

[00:22:00] >> Molly Jacobson: Thank you so much.

And thank you listener for joining us today. As Dr. Vail reiterated several times, early detection does make a difference, so get those lumps and bumps checked out. And other signs like vomiting or lethargy or just not feeling right, sure, they could mean cancer, but they could also mean other things. So get those checked out too.

At the bottom of all of this is you and your dog. As Dr. Vail, who is a widely renowned veterinary oncologist who’s been practicing for decades and has mentored many of the oncologists in the United States, he’s saying to us, your gut matters. Your own gut, and your relationship with your dog, is the one that best informs everybody about what’s going on. If you know there’s something going on with your dog, go to the vet and see what it might be.

In the meantime, if you have more questions or are looking for more answers, you can always visit us at

From all of us here at Dog Podcast Network, I’m Molly Jacobson, wishing you and your dog a very warm Aloha.

[00:23:22] >> Announcer: Thank you for listening to Dog Cancer Answers. If you’d like to connect, please visit our website at, or call our Listener Line at (808) 868-3200. And here’s a friendly reminder that you probably already know: this podcast is provided for informational and educational purposes only. It’s not meant to take the place of the advice you receive from your dog’s veterinarian.

Only veterinarians who examine your dog can give you veterinary advice or diagnose your dog’s medical condition. Your reliance on the information you hear on this podcast is solely at your own risk. If your dog has a specific health problem, contact your veterinarian. Also, please keep in mind that veterinary information can change rapidly, therefore, some information may be out of date.

Dog Cancer Answers is a presentation of Maui Media in association with Dog Podcast Network.