Hello, I'm Antony Chadwick from the webinar Vet welcoming you to another episode of Vet Chat, the UK's number one veterinary podcast. And I'm super pleased and honoured today to have Doug Tarm, who is one of the, is the professor at Colorado State University in oncology. Doug and I go back quite a far away.
I remember us meeting up fairly early in webinar vet's history at a, BSAVA Congress and you were very er kind enough to do a webinar for us and have er continued to present and er I know how many people really enjoy. Listening to you on webinar, Doug, but I think this might be our first podcast or have we done one before? No, I think this is the first one.
So yeah, it's fantastic to get you on the podcast, obviously a bit more chatty and interactive, but . I, I always ask you when we're on a webinar what the weather is like and I suspect it's gonna be sunny because of course Colorado has pretty much wall to wall sun even in the winters, doesn't it? It sure does.
It's it's going to be a beautiful day here. 26, 27 degrees, sunny, yeah, it's a great time of year. And, and Doug, I suppose, you know, with all the sun that you get over in Colorado, are you a, I, I also know, having been over to Colorado, it's a beautiful state, but also having listened to colleagues like Rod Rosiechu many times, you know, you don't see many fleas in Colorado, but maybe, you know, the negative of not or the positive if you like, of not seeing fleas, .
Is that there are is a negative and with the sun and the height, are are you a bit more prone to, to skin cancers in Colorado than maybe in in other states in the US? Yeah, I think we probably are. So, as we were saying previously, I don't really have a good comparator, so I don't know how many cases are seen in other parts of the country.
I mean, thinking back to my time in, in Australia, we certainly saw plenty of skin cancer there, as you would expect. Thinking back to my time in Wisconsin, yeah, I think we probably do see more here and, you know, I think it comes in two, in two common flavours, the two things that we see most common that we know are sun-induced star. The cutaneous squamous cell carcinomas in the cats.
So I think we all have seen the, the white kitty cats who get the lesions on the tips of their ears, on their eyelid margins, and sometimes on their nasal plantum as well. And that's very common. We, we don't have an enormous cat population here, but that is something that we see with some frequency.
And then the other sort of sun-induced skin disease or skin cancer that I think we've probably all encountered is the the sun-induced. Hemangiomas, hemangiosarcomas, to some degree, sometimes squamous cell carcinomas that often occurs sort of in the, in the light-haired, or light-haired, light skinned kind of dogs that like to sunbake out on the, on the back, on the back deck, so commonly affecting the inguinal region and those can often be a management problem too. Not so much because any individual lesion is tough to treat, but they can get so many of them that that can become a management issue.
So yeah, I do think we see, we see a bit more of those than probably some other places around. Obviously living in Australia or in Colorado, human or or animal, I presume sunscreen is often a preventative measure that you would, you would use, but of course, humans won't lick off sunscreen, but maybe cats and dogs are a bit more prone to. Yeah, they sure are, and that's very challenging.
So, it's really, it's really tough for the cats obviously because, the, the kind of locations where we, where we see these lesions occur are really not amenable to applying sunscreen, you know, the nasal plenum, they're going to lick it right off. You don't want to get it too close to the eyelid margins. So those are just unfortunate locations for this.
And yeah, and the dogs, it's usually the inguinal region where we see this and you're absolutely right, they, they do tend to just go after it. As soon as you put it on. So that's really not a very effective treatment generally.
So in the kitty cats, certainly the best thing we can do is sun avoidance. So you've got an outdoor cat, make it an indoor cat, and that's good for a lot of other reasons too, right? Controlling the wild bird population and avoiding other sorts of mishaps like getting hit by cars and things like that.
It's a little bit harder with the dogs, right? They have to go outside. So one of the things that's really interesting actually, is there are several companies that are making sun shirts for dogs.
So they, these are these sort of neoprene or, sort of stretchy lycra SPF sun shirts that some people are certainly putting on their dogs if they do like to go out and, and, you know, sit in the back garden and, and bake in the sun. And they're actually quite effective. They're light enough that even in the middle of summer, they don't seem to really Sort of, you know, make the dogs overheat and, and it's a really good option if you've got a dog that simply will not stop, laying about in the bright sun.
So it's really nice to see those products become available. And I suppose as you say, sun avoidance, if you can't stop them going out, at least maybe keep them in between sort of 11, 3 to 4 o'clock each day, which is when the sun is out. It's, I only, only mad dogs and Englishmen go out in the midday sun, don't they, Doug?
Yeah, no, that's, that's obviously really great advice if it's feasible. Doug, obviously we're talking about preventative. I mean, wouldn't it be great if we could just stop cancer happening in the first place?
I mean, it might put you out of a job, I suppose that would be the only problem, Doug, but obviously, you know, dogs don't smoke, etc. They don't drink, those sort of common things that would cause cancer in in in humans, we can mitigate against a bit, but of course there are, you know, many things that cause tumours. Do you think there's ever gonna be a time, When we can actually sort of.
Prevent tumours happening in the first place? Well, the, the sun avoidance thing is a great example of, of some simple strategies that we can use to reduce certain kinds of cancer that can be problematic. I think a great example obviously is over the last 30 years, all the work that's been done with feline leukaemia virus and the tests that have been developed, the management strategies for dealing with positive animals, the vaccines against, against the virus have really changed.
The landscape of feline cancer in a very positive way, right? So we're not seeing these young cats getting lymphoma, and dying at a very early age. So that's been really quite revolutionary actually, and I wish there were more examples like that.
Obviously on the human side, we have the, the human papillomavirus example where, that vaccines addressing that virus have really almost eliminated. The incidence of certain kinds of cancer in humans, which has been just absolutely wonderful to see. In a strange way, maybe it's unfortunate that we don't see more animal cancers that are caused by viruses because then maybe we could develop a vaccine against them and and actually sort of have a successful preventative strategy.
But, one of the very, very simple things that does seem to potentially mitigate risk to a degree is maintaining an optimal weight for your pet. So we do know that obesity. Does tend to be a predisposing factor for certain kinds of cancer.
The one that's probably been studied the most is bladder cancer, actually, where we think all that extra adipose tissue actually serves as a reservoir for certain kinds of carcinogenic chemicals that can build up and then be excreted into the urine and as a result, increase the likelihood of, of toxicity to that urothelium in the bladder. . But since, since you brought it up, we actually have a very ambitious vaccine programme that's going on right now to, basically kick the tyres on a, on a vaccine strategy to prevent multiple kinds of cancer in dogs.
So this is work that we're doing in collaboration with, a guy called Stefan Johnston, who is a professor at Arizona State University. In the Phoenix area and actually has a company called Calvary, also based in Arizona that's working to, to develop this technology. So one of the things that's always been incredibly challenging about developing vaccines against cancer, especially preventative vaccines against cancer, has to do with the fact that the the antigens, right, that are present on cancer cells.
Can be a little different than the antigens that are present on normal cells, but they tend to be unique. So even if you look at the same kind of cancer, the things that are wrong with one cancer cell from one patient are not going to necessarily be the same things that are wrong with another patient with the same cancer. So it's very, very challenging to develop a vaccine that's going to target both of those cancers at the same time, especially before they've even happened yet.
Also, viruses, bacteria, funguses are incredibly foreign, right? They are just, they look nothing like anything having to do with the normal body. So it's very easy to sort of Encourage the immune system to, to attack those.
So the changes that are present in cancer cells are very, very subtle compared to that. And right, and getting the immune system to turn on to those very, very subtle changes can be much more challenging. So, the approach that that my colleague Stephan has taken, which is really remarkable, is he's actually found a new source for looking for these, these tumour antigens where other people haven't looked, and historically what people have always looked for are mutations in the DNA.
So we know mutations in DNA can turn on certain cancer promoting genes or turn off certain cancer pre preventing genes. And when you see those, those mutations, those actually turn into changes in the protein, which can theoretically be recognised as form by the immune system. That's great, but as I mentioned, most of those are not conserved across individuals.
So, what he's actually found is quite interesting is that there's another set of these what are called neo antigens, these, these new foreign antigens that actually occur as a result of Abnormalities in RNA processing. So we all remember DNA goes to RNA, goes to protein. So everybody's been looking in the DNA.
Actually, Stefan's been looking in the RNA for these alterations that occur, and it turns out that there's quite a large number of these RNA processing errors that occur that result in neo antigens, and these seem to be the same. From individual to individual with a certain kind of tumour and even the same across different kinds of cancer. And so basically the vaccine that we're testing is looking at a series of about 30 of these RNA processing derived neo antigens that seem to be present in a whole bunch of different kinds of fairly common dog cancers.
So hemangiosarcoma, osteosarcoma, lymphoma, mass cell tumour, soft tissue sarcoma, histiocytic sarcoma. I think there might be mammary carcinoma, a couple of others, I think. So, the, the vaccine that we're testing.
Is actually being looked at in 800 dogs in 3 sites around the United States. So here at Colorado State, at University of Wisconsin-Madison, and at the University of California Davis. So when the study was getting started, we screened about a little more than 900 dogs with good physical examination, cytology of any lumps or bumps, blood work, chest X-rays, abdominal ultrasound.
To make sure that these dogs were completely healthy at the time of, of entry. They didn't have any hidden cancers that no one knew about or other serious medical problems. And then these dogs were randomised actually to receive the vaccine that I just mentioned, or a placebo.
And the placebo actually is, is the same exact adjuvant, the same exact, you know, sort of immune stimulant that's co-administered, and a bunch of random peptides. So pretty, pretty good control. We didn't know who was getting what, the owners didn't know who was getting what, the dogs certainly didn't know who was getting what.
So we'd say it's a triple blinded study. And then we followed those dogs for 5 years. So these are all dogs that were at either average or increased risk for death due to cancer according to sort of the published literature.
And yeah, we're actually the end of this month marks the end of 5 years since this study started and we're about to send all the data to the, to our statistician who's going to tell us whether it seems like it did any good or not. What we can say is that it appears to have been very, very well tolerated, so there was no sign of any adverse effects from the vaccine that we can identify. So that's certainly great news.
It does appear that the majority of dogs who received the actual vaccine did develop an immune response against those, those antigens that that were being targeted. And again, that was, that was done by my colleague, Stefan and his lab, who was unblinded, but all the people who were looking at the dogs are still blinded. We don't know who is getting what.
So it's a really exciting time. So check back in about a month and we actually may have some, some data about that. So, there's a few different things that I think are obviously quite intriguing about that.
So one obviously is this may be something that we can actually give to our pets that might actually help them not develop cancer or. Maybe it doesn't actually prevent cancer permanently, but maybe it delays it. So I think that would still be an incredibly useful thing if we got an extra 123 years of excellent quality of life before cancer developed, I think that would be a win.
So you know, a vaccine that could actually be used in our, in our canine patients would obviously be very exciting. But from a scientific perspective, I think the other thing that's really intriguing about this is I think it would really provide. Critical data to suggest that this same approach should be looked at in people.
So there's very, very nice data again from Stefan's group saying that this seems to work really nicely in mice, but getting a, getting a tumour to not grow in a mouse, that, that can be pretty easy. So the bar is not very high there. I think the fact that what we're seeing in our patients are these spontaneous tumours that are developing in dogs with a normal immune system that are exposed to the same household chemicals and lawn chemicals and breathing the same air and drinking the same water, as we are, I think really lends credence to the .
To the legitimacy of the results that we may see. So if in fact this does look like a positive study, I think it's going to be awfully hard to, to not. Take a close look at this in people too, and that would be very exciting, obviously.
So yeah, stay tuned. We're, we're really looking forward to seeing what the statistician tells us very, very soon. Fantastic.
And I suppose, you know, Colorado State has such a fantastic reputation, you know, but particularly within oncology. So I, I suppose you're seeing a lot of clinical trials coming through the university and are there any other things that obviously you can tell us about where you, where you see interest and promise, you know, maybe for the next 3 to 5 years. Sure, yeah, I mean at any time we have sort of between 15 and 20 clinical trials that are going on here just in our cancer patients, and they, they fall into a few different bins.
So, one of them is certainly somebody here has an idea and we decide we're going to write a grant and see if we can get funding to to look at some new interesting questions, so. We've done a few studies like that. We, we always have studies like that going on.
I think one of the ones that's more interesting, that sort of falls into that bin is actually a study that we're doing that's funded by the American Kennel Club. That's looking at a treatment for lymphoma that doesn't involve any injectable cytotoxic drugs. So all of the drugs that we're using are either orally administered or one of them is an injectable, but it's not a cytotoxic.
And the reason that this is, is really interesting is because one of the, the major sort of limitations to being able to deliver good care for lymphoma and a lot of other cancers is most general practises aren't equipped. To handle these injectable cytotoxic drugs. So an awful lot of dogs go untreated because the, the local vet can't, can't administer the drugs that we know work and and maybe it's 5 hours one way to the nearest oncology centre.
So if we can come up with a, with a treatment that, yeah, maybe it's not as good as the gold standard but is, you know, better than palliative care. That actually can be handled in a general practise situation. I think that's filling a really, really important gap, that, that could, could really help out a lot of dogs, whose owners can't make it to see an oncology specialist.
So, we're closing in on the end of that study as well. So all of the dogs have been enrolled in that study, about 30 of them. And we're just kind of waiting for the data to roll in on a few more of these dogs before we're able to say for certain, is it a thumbs up, is it a thumbs down.
But so, so that's one of these what we generally will call an investigator initiated trial. So somebody here comes up with an idea, find some money, and we, and we do that through our clinical trial service. But there are sort of two other important kinds of studies that we do too.
So one are studies. Where we're trying to answer a question that might be helpful for human cancer therapy development. So can we use dogs as a model to answer usually some very specific question about how a drug works or what kinds of tumours that might work best against or what biomarkers we should be looking at to know if the drug is working, etc.
Etc. Etc. That are somehow going to make the drug easier to develop in people.
So we usually will have a series of those kinds of studies that are going on. Some of these are funded by pharmaceutical companies. Some of these are funded by, oh, I don't know, like the National Institutes of Health, for example, but again, all really sort of looking at dogs with cancer specifically as a translational model.
So don't get the wrong idea here. We still are hopeful that that the, the dogs that are being treated as parts of these studies are still going to derive benefit, right? So we're not using these, they're not like little furry test tubes where we're just, we're just studying them and it's not going to do any good.
No, we're we're trying to do two things at the same time, right, which is help out the individual patient that we're seeing, but at the same time, learning some things that might be helpful for benefiting yeah. And then the third kind of study that we would be doing would be sort of what we call our, our dogs for dogs sake studies. So yeah, maybe there's a veterinary pharmaceutical company or or a therapeutics company that has a product that they're trying to develop.
And can we answer questions about that product that might eventually lead to something new that's sort of specifically for our pets? We'll often have Those types of studies going on as well, not just with drugs, but with monoclonal antibodies or vaccine strategies or devices, for example, new surgical techniques. I mean, all those kinds of things.
So occasionally we'll do studies with imaging in the same sort of way. So, are there new imaging techniques that we could use that might be helpful or help us learn things about how to better treat pets or humans in the future? Yeah, so all those are kind of part of what we do.
And we actually have a large team that's responsible for overseeing those studies. So we have a full-time, board certified veterinary medical oncologist, Kristen Weiszhar, who actually supervises that programme, and then we have a master's level coordinator, two veterinary technicians, an intern, a veterinary intern who are all dedicated to the clinical trial service. And then one of our medical oncology residents is actually rotating through that service at all times, and I think that's a really interesting opportunity for our trainees.
So the, the residency here is a 3-year programme and I think during the 3 years of the residency, they probably spend 25 weeks, exclusively seeing patients on the clinical trial service. And as far as I know that may be an opportunity that isn't isn't provided in in that format for any other residents in the country and I think the fact that we can offer that exposure to our residents is, is really wonderful. So maybe some of those people decide that they somehow want to incorporate clinical research into their careers and maybe there'll be more people who are actually out there doing this kind of, this kind of work in the future.
And I, I will editorialise that this is something that can actually be done very successfully in a private practise situation. So this isn't something that is so esoteric or so complicated that it can only be done at university. So I have some colleagues here in the states who are really extremely proficient at doing clinical research in in private specialty practise, so.
Listeners out there, if it's something that you think you might be interested in, you can, you can actually do this in a practise situation quite successfully. I think it's interesting seeing that we can help humans, but obviously the big brother is and often has more money in the medical profession, so some of the treatments. That have come in, it's good to see that we're able to piggyback off some of that and potentially use them, although obviously, dogs and humans aren't the same, so presumably some medicines developed for human use, you know, are just not suitable for use in dogs.
OK. Yeah, that's you've hit on a, on a, on a real hot button issue, I, I think these days because you're absolutely right that there's just this enormous number of really interesting and, and, you know, quite spectacular medicines that are now approved for just a variety of different kinds of cancer indications in, in humans and it's sort of our natural, our natural inclination to want to sort of take a page from the human book and, and try those same medications out in our, in our canine companions. And I don't know how it is in the UK, but, but here in the US, we actually have a lot of compounding pharmacies that are capable of getting, getting, .
Some kind of of drug that resembles the drug that is actually approved for human use, stuffing it in capsules and then selling it. And it's very much of a caveat Mor type of thing here. So you don't really know for certain what you're getting.
So is it actually the same chemical? Is it a different salt form? Is it, is it orally bioavailable?
Yeah. So those are all things we don't know. Is the right amount being stuffed into the capsules?
We don't know that either necessarily. And then on top of that, for many of these drugs, we simply don't have the information about how much should we be giving, how frequently should be giving, we be giving it. Is that enough to actually do any good?
We don't have that information in a way that's, that's very systematic, which is really unfortunate. But again, it doesn't stop people from sometimes reaching for these medications and and trying to give them despite the fact we really don't know if they're safe or effective. So actually one of the other studies that we have going on right now, is a study to try and Bridge that gap a little bit.
So we're actually studying the, the pharmacokinetics of 5 of these targeted agents that, again, people have been using in humans for a really long time. People are starting to, to use them in veterinary medicine, even though we don't know how to use them. So, We're, we're looking at again, if we give a dose of these medications that's accepted, the dose that people are using, even though we don't know if it works, are we reaching blood levels that should do any good?
So just as a very, very early first step to say, are we even in the ballpark here? Is there any chance that. We're going to be able to, to give enough of these drugs to, to a dog to do any good.
So that's another ongoing study that's, that's helping to sort of answer a question that I hope will be very practical and useful for everybody out there who's, who's considering using these drugs in, in, in canine cancer patients. So stay tuned for that as well. We're, we're 2 drugs down, 3 to go.
Now really and and you were obviously talking about Professor Johnson down in Arizona. I mean, They have it tougher down there, don't they? I mean, you guys in Colorado have it easy, you don't have fleas.
And then of course you're not in Arizona so you're not getting the valley fever, so when something comes in. You know, things like fungus can complicate, can't they, and, and make it look like cancer where it isn't so . In in that sense you've got an easier job, Doug, because you haven't got all these confounding factors.
Yeah, it, it sure can to a degree, as I mentioned earlier, I practised in, in Wisconsin for quite a while and up there, we worry about a different fungus called blastomycosis, which is quite common. And again, down in, down in the south of the country, they worry about coccidioidomycosis or also called valley fever. Again, when I, when I practised in Australia, there was a species of Aspergillus that could cause lesions that mimic cancer.
We don't really see that here either. So right in our little central part of the country, we are actually kind of fortunate that we don't really think a lot about about fungal disease as one of these sort of cancer confounders, the way we did, the way people do in other parts of the country. So that does make our job a little bit easier, but it does make it also very important for us to ask a lot of questions about travel history and our patients when they come in.
Hey, has your dog spent any time up north? Has your dog spent any time down south? Because that does ratchet up or down, our index of suspicion for fungus.
And one of the things that's actually quite interesting and a bit concerning is potentially thanks to climate change. We are starting to see occasional cases of valley fever occur in the, in the far south of Colorado, where again, previously that was never something that we saw. So it, it's starting to become something that maybe needs to be on our radar slightly more, but yeah, we are fortunate that that that's not something that we need to worry about as a, as a cancer mimicking thing here in Colorado.
In those dogs, for example, that have bone lesions. Or those dogs that have pulmonary opacities that could either be metastatic disease or could be fungal granulomas. Yeah, not such a big deal here in Colorado, which is for now, might change in 20 years, but for now, not such a big deal.
And I think it just shows the benefits of, I used to do dermatology referrals and obviously not a specialist level, but you know, certificate from the Royal College. And one of the blessings I always said was I have an hour with the client and with the patient, and that time really allows you to take a good history, because if you've got 10 to 15 minutes, taking that travel history may just be very, very difficult. So we, we are blessed by having that longer time with our, with our patients, aren't we?
Absolutely. I mean, we're, we're kind of very similar here a typical, sort of initial appointment is probably 45 minutes to an hour and because again we're, we're a teaching hospital, our students generally are the ones that that kind of go in and get that history and they've been instructed to be very, very thorough when they're obtaining that history and that's one of the questions that we make sure that they always ask. So, but yeah, I mean, even in a, in a practise situation in that specialty situation, I think it's very, very common to have 45 minute initial intake appointments so we can be thorough to look for those confounders, those additional pieces of information that might change what we do or how we do it, and I, I don't think that's ever gonna go away and that's a real critical part of what we do.
I found one of my key questions was always diet. And quite a few of these dogs would come on a food trial, but when you actually quizzed them and you said, right, you're on the hypoallergenic diet, you know, whatever brand that was or if it was home cooked. And what else are you feeding?
Oh well, I give him a piece of toast in the morning with his cup of tea with a bit of milk in, and you suddenly realised that the this very food trial that presumably the vet thought was being done very well was of course not being done, so it's it's always good to take a good history. Absolutely. You know, for us, one of the other big things is, oh, what other medications are you giving?
Yes. Oh, so, OK, you know, you're giving the non-steroidal that your vet prescribed. Any any herbs, any supplements, you know, any, any, you know, here's any, any CBD gummies.
I mean, all those kinds of things and, and actually one of my colleagues, Doctor Susan Lanna here about 15 years ago did a really interesting study looking at the use of sort of complementary and alternative type strategies, not only supplements, but a variety of other things as well, you know, reiki and intercessional prayer and, and chiropractic and acupuncture and all those things. And one of the things that was actually quite interesting about the results of that study. Was that a large number of owners.
Chose not to share the information about what they were doing with their vets. And it, it really required very, very pointed and very, very specific questioning in order to get that information out of an owner for whatever reason. Oh, I think my vet, you know, my vet won't care or my vet's going to think less of me if, if he or she knows I'm doing this other thing.
And yeah, it was far, far more common than we would think based on, for example, the records that we got from the referring veterinarian. So, and again, it all goes back to, to really being very, very detailed in that history gathering and and asking the right questions. Doug, that's fantastic.
As always, I always enjoy listening and speaking to you and as we say at Webinar vet, if you learn one thing about something that you can take into your clinical practise, then it's worthwhile and certainly my one today was just that link with obesity, which obviously we talk about, you know, obesity and and increasing cancer, but I didn't realise that there were some of these chemicals going into the urine that obviously just made it . Much more likely that that cancer cells would begin to appear in the bladder, so thanks for that little gem as well. Anytime, my pleasure.
Thanks so much, Doug. Thanks everyone for listening, hope to see you on a podcast or a webinar very soon. Take care and have a great day.
Bye bye. Thanks.
