Hello, it's Anthony Chadwick from the webinar vet welcoming you to another episode of Vet Chat, the UK's number one veterinary podcast. And we're very fortunate today to have Sarah Mason on the line. Sarah is a veterinary surgeon who specialises in oncology and radiation treatment for oncology, also a Liverpool graduate.
So really good to have you on the, on the podcast, Sarah, and thanks for agreeing to come on. That's OK, thank you. It's a pleasure to be here and I look forward to chatting to everyone today.
So, you, you were, didn't take the sort of the obvious route, but probably the more suitable route into oncology by doing a degree first in biology and a PhD in in cancer medicine, didn't you, and cancer research. Yeah, so originally I actually wanted to be a scientist, a lab scientist, so I studied molecular biology at undergraduate, which was great. It gave me a really good grounding.
And following that, I did a PhD in a cancer biology lab. So I looked at tumour suppressor genes and the interaction with oncogenes, which are basically the part of the hallmarks of cancer, things that go wrong, get disregulated and cause tumours to develop. Because it is amazing in a sense, how we're able to shut some of these cancers down without anybody knowing, you know, the human immune system is an amazing thing, isn't it?
Oh yeah, I mean, the progress that's been made in human cancer biology since I did my PhD is just amazing. We understand so much more since the human genome was sequenced. Now we have the, the dog genome at least has been well sequenced and we're we're making quite good progress into Genomics of canine cancers.
There's a number of companies now that will actually sequence cancer genomes. Partly to provide more information with regards to prognosis and mutations that we may be able to target for treatment developments, and partly to a certain extent to guide us in personalised medicine and therapeutics for those dogs. And certainly, that's the way forward in human cancer now is personalised treatment, depending on what mutations you have in your particular tumour.
Yeah, it's, it's very much when you look at . You know, going back in time and, and our drugs were very much sledgehammers trying to to put in very small nails, weren't they? So the, the likes of drugs like prednisolone are have actions all over the place.
They're not just against the tumour, are they? Yeah, and that's the thing with chemotherapy, which it's still, chemotherapy is still a very good treatment for many cancers in humans and in our pets, and it still forms the basis of a lot of cancers that we deal with in terms of treatment. But certainly in humans, there's a few examples of cancers that chemo is no longer indicated, and because of improved molecular targeted drugs.
We're certainly sort of getting there with dogs. When I was a resident, very much everything got surgery and chemo. And now there's more and more evidence suggests that chemo isn't necessarily effective for some tumours that historically we thought it was.
But they may do better with some of the limited amount of molecular targeted drugs that we have available to us. In animals. So it's, it's slow progress, but definitely it's a growth area and we're making steps towards having more precision drugs rather than, like you say, sledgehammer effects with chemotherapies.
Just going back a little bit in time, obviously you went to, well, I would say the best university in Liverpool to do veterinary medicine, the best city coming to Liverpool myself and also graduates. But stayed around quite a bit after, after university, although you, you did do some time in general practise, which I think is so, so important, you know, even for somebody like yourself as a specialist, I think to have that time as a GP does give you both sides of the equation, doesn't it? You can understand from a GP perspective and from a specialist perspective.
Yeah. Oh, absolutely. I had a great time in general practise and I deliberately went to general practise.
I could have gone straight to internship after. My vet school, but I wanted to get that experience the GP and honestly, some of the things I saw as a GP and learned from still sticking my mind now. When I see some of our patients coming in for surgery or things, I think, well, actually.
You know, some of the surgeries I did in general practise are not what I would expect a diploma surgeon to do for my patients now, but I certainly learned a lot about very basic things like wound healing. What animals are capable of, what they can recover from when people have very limited budgets, for example. So, you know, I worked in the Northwest around St.
Helens and Wigan, and, you know, we saw clients that had reasonably good budgets, but we also saw clients that had nothing. And I had to manage cases in all different across disciplines, neurology, medicine, you know, surgical, where you were doing your absolute best on a shoestring. And What the outcomes could be.
I know, you know, it's very worthwhile to try and treat patients. Yeah, yeah, yeah. I think we are probably more holistic than doctors because having done that GP thing as well, you probably.
You look at the whole patient rather than the lump that's attached to the patient, which I think is so so important as well, whereas if you become super super specialised as I think they do more so in in the human field. There is a danger that, you know, I have glaucoma, I go and see my ophthalmologist. You know, I've never had an examination apart from my eyes.
Yes. So you can miss things by having that sort of approach, can't you, as well? Yeah, absolutely agree.
And that is something as a specialist, I try to put, remind my junior that so when I'm training residents and interns, I always remind them, you may be in oncology, but actually look at the patient. The owner says the dog has not eaten for 2 days. Is that actually because of the chemo we gave it?
Or has this dog, for example, famously, one of my patients ate a cord of the cob at a barbecue and came in after, I think it was the 4th chemo. And well, like, this dog hasn't been unwell with the 1st 3 chemos, so why is it suddenly unwell this time? And then you have to think about that and palpate the abdomen, and sure enough, There's the cold on the cob that's causing it to be ill, whereas it's removing.
Exactly. So yeah, so I, you know, same thing. If we have dogs with neurological symptoms, it's not chemo very, very rarely causes neurological symptoms.
The dog probably has a disc. That's a lot more common. Yeah.
Then chemotherapy causing a spinal lesion, for example. And, and I think as, as you said before we started, so I'm not showing off here. You know, it's contextualised care as well as if you've got a 16 year old dog with a tumour, but it's got a heart problem because you've listened to its heart, it's probably gonna change the way that you treat it, isn't it?
Oh, I mean, absolutely. I mean, very recently, actually, I had a patient who came in. With a tumour that actually was referred to radiation.
And as soon as I examined the dog and listened to its heart, I was just like, this is not right, you know, the, the dog had an arrhythmia and a murmur and The first thing, you know, our anaesthetists won't anaesthetize a dog that looks unwell with a cardiac, cardiac signs. And we had it scanned, and sure enough, the dog had actually a much more significant heart problem that was likely to, unfortunately, kill it before the tumour was going to. And exactly.
It changes your treatment plan. Exactly. It's not then not appropriate for me to put that dog through a definitive treatment protocol that might be fairly long.
And require multiple anaesthetics in some patients. Yeah, sure. Obviously you were at Liverpool for quite a period doing your intern residency lecturing, you then spent some time at Cambridge, and then, as along with the oncology being board certified in that, you've, you've gone out to actually get that radiation, experience and specialism as well, so that's I think a fairly new.
Diploma as well, isn't it? Yes. Yeah.
So the radiation has always been around in the UK as always. I've been an oncologist, and actually, it started at Cambridge. So I was very fortunate to go and work with Jane Dobson there.
Where, you know, the place where it all started. And I have always worked with radiation. Liverpool has radiation in Cambridge, and my job now at Southfields is a radiation centre.
It's really important to me as an oncologist to have access to that because it gives me so many more strings to my bow, if you like. So, yes, the radiation, first of all, the European Board of Veterinary Specialists allowed some people who had experience in radiation to join as specialists. And that allows a college to be formed.
And then they rolled out the, what was called at the time, the add-on programme. So, I, I did the add-on programme. So I was the first person to do the add-on programme by training.
So, I trained mostly at Cambridge, and then I moved to Southfield and finished my training there. And then I sat, I was the first person to sit the exams for the new diploma in 2019. Yeah.
Then we had 2 other people have gone through that, but now we actually have a, a specific subspecialty for radiation, which I'm on the committee for. So I do that as a voluntary job on the side. And we now have a proper residency programme for radiation oncology in Europe, and we have our first 3-year resident enrolled.
So it's, it's definitely, again, a growth area. An area that people are becoming more interested in. And it's great that we now have a special, a specialty college for radiation therapy as well, because it, it's definitely a key.
Treatment option for many of our patients. And am I right in saying that it, it's become a lot more precise because obviously the radiation used to be over a wider area, whereas we can really beam it specifically. How does that work?
How does that, is that based on imaging as well to know exactly where we have we have the best radiation machine in the UK for sure and I think in Europe. In regards to its precision. So there's various components of the machine that allow us to be precise, what is the couch.
So, the table that the patients lie on can be moved in 6 directions. So that allows us to be very precise in positioning them. We also have a built-in CT on our radiation machine.
So we can literally in half a minute, get a real-time image of the patient's positioning. We can do respiratory gating. So if you imagine a big dog when it breathes, if it has an intrathoracic or an intraabdominal tumour, or even an external thoracic tumour, it moves, and it can move as much as like 1 or 2 centimetres of the big dogs taking deep breaths.
So that allows us to reduce the imaging allows us to reduce the volume of tissue we have to treat to avoid missing it. So, historically, you would have to say, OK, this dog might move a couple of centimetres, so we'll draw a big circle around it to treat more tissue. Now, we can say we can be much more targeted.
The advantages of that, we can reduce treatment, side effects, which is really important. So the dogs and cats have less side effects. We can reduce treatment times because we don't need to worry so much about sparing the normal tissues.
So we can prescribe bigger fractions, where we used to have to be a lot gentler with our daily treatments. We can give more treatment in a shorter time period. Because you're giving that specifically against humans rather than normal cells.
And one of the best things we can do now at Southfield is, it's called stereotactic radiation. Which is a more ablative type of radiation. So it, it requires the precision we have on our machine.
And we can now treat things that historically might have had to be treated in over 34 weeks. We can now treat in 3 to 5 days. Yeah, it's amazing.
Because we can give the same kind of dose to the tumour. But in a much less time. So.
Historically, how, how did that work with oncology? Was it, you know, a, a dog came in or a cat came in with a tumour, and would that often be surgically. Sort of removed and then radiation would follow it up, whereas now we're actually just treating the tumour rather than doing the surgery, aren't we?
Exactly. So, so it's a very, it's a very good question. So there are still tumours that will benefit from having surgery and radiation that that hasn't gone away.
So specific things, for example, soft tissue sarcoma, we would want to reduce. So surgically. Take as much as we can.
Obviously, surgery is always the first choice if it can be completely removed. In situations where it can. Yeah, exactly.
Then reducing the disease burden and then radiating it is better. But there is now the option of actually doing a radiation, like ablation in specific patients. So this is where contextualised care comes in.
So if, for example, the, the client doesn't want the dog to have surgery for whatever reason, the surgeons think it's a Risky area, they might not be able to palliate it for more than a few months, for example. Then we can use radiation on the girl's disease at ablative doses. And actually, we might get as good or better outcomes as the dog would have with surgery.
So, a good example of this is, it just came to my mind because it's, our oncology, European Oncology conference in the next few weeks. And I'm just preparing my abstract about anal sac tumours, looking at, one of our radiation protocols on dogs that have had surgery. And actually, my feeling as an oncologist now having seen a lot of anal sac tumours is that.
There shouldn't be a just surgery option for these dogs. I would say that radiation alone on gross disease. Provides better outcomes than surgery.
It keeps the tumour in remission, whatever that may be partial or full for longer. And it has generally less morbidity. And the other option is surgery and radiation combined.
Personally, as an oncologist, I would not recommend to any client of mine that they have just surgery. They either commit to the surgery or radiation, or they go straight for radiation. Or they do palliative care, which is perfectly appropriate for many of these dogs because they still have a very good quality of life and it's a slowly progressive tumour.
. But yeah, that's a definite shift from historically when surgery was, I still see it in papers. Surgery is the treatment of choice. And a lot of the anal sac tumours are adenocarcinomas, aren't they?
Yes. Yeah, yeah. They come from the apocrine glands in the anal sacs, obviously, and they, they're quite radiation responsive.
It's actually a really interesting tumour for me. The, the way they behave is very interesting that we have again, targeted therapy, so we can Use palladia, which is to sarin phosphate, actually controls a lot of these tumours, even metastatic disease, reasonably well. And we don't know exactly what mutation that is, or whether it's just off target effects that are working from the drug, but definitely.
It's one to watch in terms of. Having potential. Further therapeutic options.
And at the very back of my mind, so this may be complete gobbledygook, Apocrine adeno adenocarcinomas, they cause an increase in calcium, is that one of the ways that we can, yeah. So about 20% of dogs that have them present hypercalcemic. And it's very interesting because We can radiate them and shrink the tumour by killing the tumour cells, but only about 50% of them will become normal calcaemic.
So there's all these kind of clinical questions around. And there's another example of how we make decisions for treatment. So, a dog that's, it used to be that hypercalcemia was a negative prognostic indicator.
Well, of course, it is, if it doesn't respond to treatment, because that's going to make the dog feel unwell. So I, you know, I feel like it's just a. A consequence rather than a prognostic indicator.
So if we are discussing with clients of a hypercalcemic dog, it very much depends how well the dog is, what we would recommend. So, you know, to send that dog to surgery, and then have to have 2 weeks to heal, and then have to come and have the radiation plan and then start 4 weeks of radiation. That's a long treatment pathway for a dog that actually might not be well enough to go through it, as opposed to maybe it's better in that dog just to get it.
You know, get it planned quickly on the table and radiate it over 2 weeks. Because you can see an improvement in the ones that respond. You can see them improve as quickly as a few days.
Would, and if they were doing better, would that be an argument then to go on to do the surgery, or once you started the radiation, is that you, you. Yeah, that's a that's a tricky one. So some tumours you can do radiation first and then surgery.
Probably not for an anal sac, because the radiation causes damage to normal tissues and blood vessels and things. So, yeah, that, that would be a very individual, Decision. And yes, once, once the radiation is a good question.
Once the radiation protocol is decided, you can't then change it. So a lot of clients will kind of edge their bets and say, well, what about if we start with the less intense one, and then if they respond, we can go to the more intense one and go, it's not how it works. You have to either commit to the most intense or the less intense or the, you know, When you see, you know, and I certainly see over my career, the, the progress that's been made in oncology, human and animal, it, it is amazing.
Do you think still there are people out there, you know, definitely clients, you know, we've all had the client who comes in with skeletal cats who said, you know. We wouldn't come in because we knew you'd put the cat to sleep, you know, with whatever condition it had. Are you still seeing that with.
Patient with clients and maybe even vets who who perhaps don't realise how much advances have been made and what, you know, we can do for animals with tumours now. It's, it's actually a fascinating area. I'm really interested in this, as an oncologist in general, how people, the general public, even, when they talk about cancer treatments, you know, even if you, you go, for example, when I go to my running club.
And I run with different people and they'll talk, they'll ask what I do and they'll talk about, oh, my brother had cancer, my mom had cancer. There's still very much a tendency to lump cancer together as one disease. And it's not one disease.
It's 1000, hundreds of thousands of different diseases. And we are all individuals who our bodies will all respond differently to different types of cancer. And yes, people, particularly now in the cost of living crisis, I hear it a lot when I go out to different groups and things and say, Oh, you're a vet.
Oh, well, yeah, my cat needs to go, but I haven't taken my cat because, you know, they'll charge me £40 for a consult, or they'll charge me. You know, whatever, and also people's attitudes to. The fear of euthanasia, they're still, as you say, very much a fear of, I won't take my pet to the vet because they might tell me to put it to sleep, rather than have a conversation about what the appropriate options are and how to make the pet more comfortable.
I, I think also, as you were saying, if they're comparing it with people, often people are much more unwell with cancer treatment than dogs and cats are, because we've got different sort of ambitions haven't we with treatment. Yeah. And it's very, it's very much, something I talk to clients about as soon as I have the patient in and I'm talking about treatment, I always say, it's not.
Have you had any experience personally of cancer? How was that experience? You know, if they say that they've seen a person in their family suffer and Die in a, you know, difficult way, which I, I have personally.
I always say some, it's not like that, we wouldn't let that happen. And I, I will introduce the concept of when is the right time to euthanize quite early on. In the discussion, depending on the tumour type.
You know, if it's a low grade mast cell tumour, sometimes the clients will come in crying because they think the dog has to be euthanized. And then you can give them good news. If it's a metastatic prostate tumour, then I have to have that difficult conversation.
They may not have been aware it was a metastatic tumour at the time it came to see me and then we have to start talking about How to make decisions and how to manage quality of life and things. And I think that, again, it is, I always used to say to clients, you know, with any of those sort of end of life, decisions, you know, there's 3 people in the room, there's, there's myself, there's the client, and there's the animal. And, you know, as long as we make the right decision for the animal, and if we take the animal 2 weeks too early, that's better than taking it 2 weeks too late.
Absolutely. Same a day too early is better than a day too late. Yeah.
For sure. Just obviously chemotherapy has always kind of been the mainstay or was when I was in practise, radiation is becoming more and more common. Just for, you know, vets listening in now, what are the tumours that we should really be looking at for radiation therapy and then, you know, I know you talked a little bit about at the beginning about molecular therapy and precision therapy of, you know, almost personalised medicine for tumours.
Where are we up to in that and is that is that likely to progress quickly? Yeah. So with, with radiation, I mean, pretty much, without saying we can treat anything, we can treat most things.
So most things are Radiation would have a role for the right tumour on the right pet for the right client. Things are definitely are suitable for radiation that more commonly. So, nasal tumours is one that vets will see in practise.
Nasal tumours are fairly common. They respond reasonably well to treatment, particularly stereotactic. The treatment can now be done very quickly with much less side effects than historically.
Brain tumours, we see a lot of them. I guess it's not such a GP thing because they don't diagnose the brain tumours, they send them to a neurologist who sends them to us. Absolutely, if you have a suspicion that a dog has a an older dog has a brain lesion, you know, it's a probably fifty-fifty chance it's a tumour.
So you can say to clients that, you know, they can do quite well with radiation. What else would I say? Anal sex I've talked about, for me, absolutely, they do so well with radiation.
It would, it's a shame not to include that in their treatment. Still, probably from your day, you'll remember soft tissue sarcomas, and, mast cell tumours. It's more, I would say mast cell tumours, we're definitely moving to more surgical and targeted options, but we don't see as many as I did like 10 years ago in terms of radiation.
Inclusion, but it's still valid. There's still a role for it and soft tissue sarcomas after surgery or even With surgery, things that people wouldn't even think of. So my colleague recently has irradiated an adrenal tumour.
That's becoming more, you know, where people don't want to do surgery on these because they're very vascular, they're very fixed. The risks of dying are quite high. That, you know, we can radiate them more safely.
But very precise to be able to hit that adrenal tumour, which I know is enlarged, but still quite a rare. And that's where all of our all of our technology comes in with between the imaging, the breath, the gate, the respiratory gating, and the couch and the skill of my team to be able to Yeah, to hit it. But yes, it's, it's precise, but it's definitely doable.
So. Cause I can say, even with breathing, the tumour potentially moves, doesn't it? Yes, exactly.
So that's why we need to have the machine ready to go when the tumour moves into a specific plane, we control the dog's breathing. Say, this is when we switch on, this is when we switch off, so that it's in the right place when we, when we target it. With the precision molecular medicine, that's, that's a slower burning thing.
There are several companies now, mostly US based, that are sequencing personalised dog tumour genomes, so that can be done. Sure, there's one in the UK called CanCan Diagnostics. They can give us advice as to what mutations, obviously, they find in the tumour genome, and that can allow us to then target those tumours more appropriately, but our options are a bit limited.
So, it's moving a bit faster in the US because they have a bit more freedom in the US to choose human treatments. So, for example, a EGFR mutation, which in humans responds to a very specific tyres and kinase inhibited drug. They would be able to get that quite easily.
Whereas, unfortunately for us in the UK between licencing and Problems we have importing medicines, actually, which got worse since Brexit. We might struggle a lot more to be able to prescribe something. To a dog when we have, for example, the sarinib available, because that's the following the cascade, we should really use that.
I mean, it's not impossible, but the cost of these human drugs can be quite prohibitive to a lot of owners. So finally with a, with a let's say a a mass cell tumour which you've part removed but you can't get it all out or you wouldn't worry about dirty edges, would that be kind of massives as a, as a treatment there, you know, in a difficult to operate area or an area where you haven't got complete removal, or would that be something that you would immediately go to radiation with? So that is a, that is a whole can of worms.
I could probably do two full webinars on that. So it really depends on the tumour. Depends on the grade of the tumour, mitotic index, suspicion.
I mean, massive effect is licenced for kit mutation, mast cell tumour, so you would theoretically should sequence it, but it also has off-label effects, as does Paadia. So very, very much depends on the, those things, the location of the tumour. For example, and the client's wishes.
So, again, contextualised care if the client, the, the problem with radiation is that clients have to travel to a radiation centre. There's only, I think, 5 currently working in the UK. And they may not be able to stay away from home or have the dog stay with us, for example.
So, then you would Obviously offer a TKI. And sometimes if you're worried about that dog maybe has some splenic mass cells that may or may not be. Metastatic.
Those all influence your decision about which is the more appropriate. Roads go down, but absolutely radiation is indicated for a lot of them. Is it a case, Sarah, that as you understand more and more, you realise that in some ways you know less and less, it's, it's more grey than black or white?
Definitely, definitely now, particularly with all these genome sequencing companies. And now we, you know, we're still at a stage where actually we don't have particularly good studies for a lot of what we already do, anal sex, we talked about earlier being a very good example. You know, there's a few small studies with like 20s, 15 dogs, looking at outcomes.
What we need is at least several 100 if not 1000 dogs to look at the outcomes. And then, you know, when we start going into specific mutations, well, you know, say we find that 10% of dogs have mutation X with their tumour Y, we then have to treat all those dogs with treatment A, B, C, and D, and see what the outcomes are. So there's a huge capacity out there to improve our knowledge.
Unfortunately, as you know, things move very slowly, even in human oncology and. I don't think I'll be seeing the reaping the benefits of a lot of this during my career, but I hope that the oncologists I train and the oncologists they train will be able to move forward into these areas as time goes on. That's, that's all about progress, isn't it?
Sometimes the people who start the process don't necessarily see the see the crops being reaped. Yeah. Yeah.
Sarah, it's been fantastic having you on. I learned so much from doing the podcast, and this has been no exception. Obviously it's been great to know, you know, what we can do.
There's always gonna be more, but thank you for everything that you do for all the animals under your care. Thank you and thank you very much for having me. It's a pleasure, especially two weeks before the annual European conference, which is also the first to include a radiation oncology stream.
So I'm really, you know, happy to be involved in all of these things at this point in time. Fantastic. Whereabouts Sarah Bucharest.
Bucharest, it's always good, isn't it? We always get good trips with these European conferences. So enjoy, enjoy Romania.
I'm looking forward to it. Thank you so much, it's been a pleasure. Thank you, Sarah, thank you.
Thanks everyone for listening. Hope to see you very soon on another webinar or podcast. Take care, bye bye.
