Hello, everyone. Thank you for joining this webinar on radiation oncology. I look forward to giving you an update on what's available now, compared to what used to be available and perceptions of radiation in the UK and Europe in the past.
So you should have the learning outcomes in the notes. My aims today are really to give you an overview of what we do in radiation therapy for our, mainly for our cancer patients. And we'll do that through developing an understanding of the indications, because I think a lot of people are actually unaware of how useful radiation can be in many cases.
I would like to just give a little brief overview of the basic principles of radiation. Don't worry, I won't bore you too much with physics and radio biology. Go through some types we treat, because really we do treat a significant number of certain types much more than others.
And those are the ones where owners might be googling it and coming up with their own referrals in a way. I want to give you the differences between traditional old school radiation and what is available now with our new modern machines, such as the one we have at Southfields, and then talk about communication in managing our radiation referrals, because I know how much pressure there is on general practitioners and the time limits you have on consults and the number of clients you're managing. And sometimes you a little bit of guidance on how to refer to a specialist as useful.
So Radiation is becoming more and more available. There are more facilities with much more modern treatment machines than perhaps you would talk about at vet school or have seen when you were on rotations in clinical practise. We now can do much more advanced treatment techniques, and we can treat tumours in very short periods of time with minimal side effects.
And there are more and more of us doing the training to become specialised in radiation oncology. One of the consequences of that and the internet is that clients now can easily find out about it, then many of them are much more willing to pay for it and have their animals treated. And they can research it well themselves.
So really, where we are in 2024 is that radiation. It is no longer a peripheral treatment option. It should be considered a mainstream treatment option for many, many of our cancer patients and clients should be offered it, whether or not they want to go for it is up to them.
But yeah, certainly it's much more mainstream than it used to be when I was a vet student, for example. It's not surprising. So in humans, 40% of people that have cancer can either be cured or managed very well by radiation, either by itself or combined with other treatments.
So it is a, a really big part. Many of you probably know people that have had radiation for various cancer types. There's no reason that we can't offer it to our dogs, cats, and other animals such as rabbits or small exotics in certain cases.
So the first thing is to go through the indications, what, what tumours we commonly treat, and the definitions we use for some of the treatments that we, you might hear about in CPD's or if we do an advice call, for example. So that's Normal radiation, old school, whatever people like to call it traditional, which is using fairly big fields, a bit point and shoot, maybe quite basic plans to treat tumours. And we still do a lot of that.
It's still very appropriate. But more so now, we, this is our new fancy machine. We have image guidance, so we can actually target tumours much more accurately than was possible 10 and 20 years ago.
And so people use the term IGRT to describe image-guided radiation. Most of ours now, even if we do what is physically a point and shoot, we still might use some image guidance to make sure that we're being accurate in targeting the radiation to the tumour. There's IMRT, which is intensity modulated radiation.
I'll describe that a bit more later. All of these, I'll describe a bit more later. VAT, which is volumetrically modulated radiation and stereotactic radiation, which is very defined radiation for specific indications.
I just wanted to put these in now so that in case I drop them in at any point during the talk, then we've had a brief overview, but I will talk about them in a bit more detail later. So, other terminology that is important to know is how we talk about, the indications for radiation, the clinical indications, which are, there is adjuvant radiation, and that's where we treat a tumour bed. So if the tumour has been removed with incomplete or narrow margins, then we will treat microscopic disease.
There is treating growth, or microscopic disease, which is a non-resectable tumour treatment. So a typical example of that would be nasal tumours. However, there are reasons that sometimes we may also treat superficial tumours in the macroscopic setting if it's quickly recurred, if the pet isn't unnameable for surgery, for example.
And then there's the intent of radiation, which is quite important. There is a lot of confusion around this. So when we talk about definitive or curative radiation, What that actually means is that we're delivering the radiation with the intent to give the pet the best chance of tumor-free survival and a good quality of life, but it's not guaranteed.
So I, I don't personally like the term curative because We're not going to cure. The tumour Then there's palliative radiation, which is basically just giving some radiation to control the symptoms. And that may control physical symptoms of the tumour, bleeding, for example, it often will control pain and it at least should slow down tumour progression and improve the patient's quality of life.
So palliative treatment. You know, it's probably, we probably do more palliative treatment than we do definitives. But very much the intent of treatment is actually down to the radiation oncologists and their knowledge of tumour behaviour and how likely that radiation prescription is to work for that particular tumour.
Because even within the broad spectrum of definitive, there can be many different prescriptions that may or may not offer a better chance of survival or managing the local tumour. So, it can be used in many, many ways. Like I said, the machines now can offer very targeted therapies.
So there's local treatments. We don't obviously treat, for example, widespread disease like lung metastasis. Everything has to be localised, but we can treat, for example, a solitary lung tumour.
It's non-invasive, so the patient isn't having surgery. There's no wound. They may have side effects, which obviously need managing, but many patients now don't because of the accuracy of the machines.
Most of the conditions we treat are malignant tumours, so we, we treat mainly malignant cancers, but also we can use radiation for benign conditions such as osteoarthritis or rhinitis or inflammatory conditions that may respond, or reduce with radiation therapy. And things that affect our choice of protocol or indication is whether there's a growth disease or microscopic, whether or not the tumour is intrinsically radiation sensitive or resistant. So some tumours are relatively non-responsive to radiation.
They need a lot more dose to shrink tumours down or to kill them, whereas other tumours are very sensitive to radiation, and they may do much better with treatment than others. And obviously, there's a lot of individual variation in tumours and patient responses. So I talked already about palliation with policy of life and pain relief.
So what are the most common tumours that we would treat that you can refer patients for? Nasal and sinus tumours are probably the most common, closely followed or perhaps even more, we treat brain tumours. So a lot of our referrals are brain tumours nowadays.
I think brain tumours have been recognised and diagnosed a lot more quickly, having now got a lot of specialist neurology services. Oral tumours, so things like squamous cell carcinomas, melanomas, fibrosarcomas, for example, we can treat. Preferably in microscopic setting, but sometimes in gross disease, .
Other examples of tumours we treat, for example, spinal tumours. Osteosarcomas of the limb, and we treat a lot of anal sar tumours actually, that's probably one of our more common tumour types. And we treat some types of lymphoma, for example, nasal lymphomas in cats.
Gross disease in the lymph nodes, for example, and some localised like cutaneous lymphomas, are actually very radiation sensitive. Microscopic disease, so scars, tumours that are incomplete or narrowly excised. We commonly see muscle tumours.
Soft tissue sarcomas, for example, cat sarcomas, which may or may not be injection sites. Again, we sometimes treat things like anal sacs or nasal tumours in the microscopic setting if they've had surgery. And ideally, that's a preferred treatment for anal sacs.
If the patient has minimal disease, then surgery and radiation is preferred to treating them in the growth setting, but it's actually quite a radiation responsive tumour, so it can be treated in either. And obviously, there are other tumour types that I, I won't go into all the possible ones we can treat. But we've done things like adrenal tumours, for example.
So anything, you know, it's worth asking the radiation oncologist if it's something they would treat, because most things actually can be treated. Whether we should treat them or not depends on other things like patient factors. So that's the basic indications.
So just moving on to the basic principles of radiation. So, to give you a general idea of what it is, because obviously most of you presumably don't work in practises that have them. Therapeutic radiation, it comes from the machine I showed a picture of the external radiation beam, and it's high energy electrons or photons.
We use them to damage the DNA of cells. We also create some damage to cell membranes and proteins and RNA, but mostly it's DNA damage. And it's a different effect from therapeutic, sorry, diagnostic, radiation.
So, the Cotton effect is just the way the electrons interact versus the, as the photoelectric effect, which you see in diagnostic X-rays. And Different target tissues that react in different ways to radiation and that's causes damage, DNA damage, as I talked about. So it causes chromosome, aberrations.
Chromosomes are then unable to go through the process of mitosis, my, mitotic cell division, and we get mitotic cell death. So the cells which are damaged by radiation will die as they proceed through the cell cycle. So that's relatively important to know because tumours don't necessarily go away very quickly.
It can take actually as much as weeks and months to see clinical responses, which is why some patients may not be good candidates if their tumour is very extensive and affecting them quite significantly. If it's a radio sensitive tumour, that's fine. They will respond very quickly, but if it's a relatively resistant tumour, they may not get the benefits of radiation quickly enough to, have You know, to, to counteract the disease that they're suffering from that's affecting them at the time.
So there's a thing called the, the therapeutic rat ratio. So it's really important to know, that radiation beams have to pass through normal tissues. And so the normal tissues will also be, damaged.
The DNA of the normal tissue cells will be damaged and those cells may die, so you Definitely get side effects. The question of how significant the side effects are is for us as radiation oncologists to minimise them. That's part of our job.
We harness the tumour cell mechanisms. So tumour cells often have defective, for example, DNA repair mechanisms. So they can, they will die with different amounts of radiation than Regular cells, because the regular cells can repair the damage the radiation causes.
So we use this as our kind of basic model for how we decide what radiation does and fractionation to give, because different tissues can tolerate different amounts of radiation, different doses of radiation, different frequencies of radiation, for example. So that's all factors in when we're making a radiation treatment plan for them. So what do we have to consider when we're treating a patient?
So, first of all, what's, what's our intent? So when we do the consult, you know, we talk to the owner and say, What, what do you want to achieve? You know, what's your best case scenario, worst case scenario?
A lot of others will actually say, I just want the shortest thing you can do to make him more comfortable. I know he's not got long or, or whatever. Other owners will say, I want you to do absolutely everything the best you can.
And, you know, we talked them through all the scenarios, because it's very dependent on patient age, comorbidities, tumour, behaviour, for example, and even within certain tumour types, they can all behave very differently in different patients. And then we have to look at. How much dose we want to give to that particular tumour, how effective that is, what the risk of side effects is, how we prescribe it, and consider the different tissues involved in the, the local area.
So how does that work? So this is one of our brain patients, he stayed with us for a few weeks, so he's outside having a walk with the kennel assistants. So the first thing we do with all our patients is we take History and physical exams.
So history with the owner. We often do phone consults nowadays because the owners don't really want to travel until they've decided what they want to do, because then it can be more efficient. So we'll often do the history and expectations and all the potential treatment options over the phone.
And then once the owner has decided they want to do something or they know what they want to do, they'll bring the patient in and we'll examine them. Which may or may not change the plan, but at least in most cases, it doesn't, because we've had a good history from the local vets or the, the preferring oncologist. And then we take into account whether the dogs have full staging.
So if the tumour spread, or if we need to do any more of that when they So that's the first steps, like any patient for good history and physical exam. And then the next step in planning and delivering for radiation treatment is we need to get some imaging. So, if your dog has a scar on its leg, and we can see it, and it's had a picture taken of the tumour and things, we can do, we don't need imaging for that because the plan is actually quite simple.
If the dog has a brain tumour or whatever, nasal tumour, obviously, we need to get a three-dimensional image to know exactly where the tumour is to be able to target the radiation accurately to it. So, usually that is a CT because the treatment machine needs a CT scan to input into the software to be able to make a plan. Ideally, we would love to have an MRI for every patient, but obviously, people can't afford that.
So we only do MRIs in specific cases. For example, brains having stereotactic radiation would always need an MRI. And sometimes we need, we always need a CT so they would get both a CT and an MRI.
And if, for example, a patient has had surgery, we might take a pre and post-surgical CT because the tissue contours will have changed before treating. And the main thing is we need to know what dose of radiation is going through the patients. So that's what the planning CT is.
The planning CT, a lot of vets will ask us, well, the vet, the patient or owners will ask us, the patient's already had a CT at the local vets, why do you need to do another CT? The reason is because we need to put them in a specific position for treatment. So we have a lot of props we use.
So one example is here on the side. This is a mask, a radiation mask that you put on the dog's head. And that helps to mould it into the same shape every time and fix it to a board on the table.
So, no, it doesn't matter how specialised the referring practise are. It's not possible to do the planning CT there because we need to see the patient. We need to put them in a position we know our machine can handle.
So, for example, with bigger dogs, sometimes the rotation of the machine might hit their legs or something, so we need to know it. We'll be in a different position. And we need to use our props to help us get the best plan for these guys so that we mini, minimise their side effects and maximise their chance of good treatment outcomes.
So, this is an example of a dog having a planning CT for an anal sac tumour. So, in this case, it's a long-legged dog. So whatever reason we chose to have it on its side, that allows the intestines to fall away from the colon and the lymph nodes.
Sometimes we might put them in sternal. It depends just on each individual patient and the preference of the oncologist who's treating them. So we can see it's in a special beanbag, and we've marked the beanbag with where the laser lines in the CT and then in the treatment machine.
Which, all of which allows us to accurately position these dogs for their radiation treatment. And these are examples of some things. So, the thing on the left is a special pillow that we use maybe for a limb, if we've got a complicated tumour on a limb, or sometimes for a cat's head, for example, to make sure their neck's in the right position or thyroid tumours.
And there on the right is an example of a bite block, which we make a dental mould for patients with oral and nasal tumours, and they're fixed onto a special, stand so that their head is in the same position each time. So these are things we use during CT and then we use them, repeat them every time the patient has treatments with us. So, just a few examples of the weird positions we use.
So, this is a thyroid tumour, the dog's on its back. And this was a sarcoma, on the dorsum, and the dog is on its, side, actually, for this one. It's just that the, the images, come out of it looking as though it's in dorsal recumbency.
So after we've done the image acquisition, we then need to do the radiation plan, which is, that's the job of me and my radiation colleagues. It's, first of all, we have to do contouring, which is drawing around the tumour. And all the normal tissues to make sure we've outlined everything that we need.
And then we use special software. I'll show you a picture in a minute to find where the beams need to go. So we can do it.
You know, we can look at the tumour and say, I think the beams will come in this way, this way, this way. Obviously, we can't do that ourselves. The machine does that, and the computer tells it where to do them.
Then we need to check the plan is appropriate, appropriate, as in clinically and physics-wise, that the dose distribution is good enough for everything, and it has to be validated. The, the machines are all computerised now. Then I'm going to let you deliver a plan that isn't clinically acceptable, and they're human standard machines.
So the, the expected standard is that what we would have if we were having radiation. So this is an example of contouring of a tumour. So, We outlined, first of all, what we think is gross's disease, so what we think is the actual tumour.
Then we draw a margin of what we think is clinical targets. So that's any tumour that's extending in there, any little tendrils or where we think it might spread, the microscopic cells. And then we have this thing called the planning target volume, which is the potential part of the patient that needs to be treated.
Now, back in the day when I was learning, These were big, you know, this dog would have had to have its brain treated because we treat. All of the blue area, which is the planned treatment volume. Nowadays, we are able to much more shrink these down with our more targeted therapies.
So, yes, I mean, it looks terrible. It looks like we're giving radiation to half the dog's brain. Actually, we did used to do that for years and years, and by prescribing carefully, the dogs very, very rarely have side effects.
So, now with our smaller treatment volumes, we can actually have an even less risk of side effects and much more targeted treatments for our patients. So this is what I was talking about, the software that we use for planning. So, for the most simple treatments, we will just tell the machine where to put the beams, and then we'll modify it a little bit, and we get these graphs of how it's affecting the tumour and the normal tissues and everything.
And for the more complicated plans, the machine does it for us, and we just have to oversee it and make sure it hasn't done anything. We have to tell it what we want. So we say, I want you to give a 100% dose to this and 90% dose to this, and no dose to this.
So we do that, and then the machine delivers the beams, based on our prescription in, in that sense. It can be a bit addictive, it can take a long time to fiddle with it because you keep thinking, oh, I need to change that, I need to change that. .
And obviously it's always choosing the best plan for the patient and the tumour. Just some more examples of how it looks on the computer. So it's a 3D image of a dog's head there on the left of the beams going through.
It's an old school treatment. And how the dose is distributed there on the right. So now we've done all this, the next step is patient treatment.
So I can talk to you now about the different types of radiation and the potential benefits of them. So just a reminder of the types of tumours that we treat and the potential outcomes for them. So nowadays, With nasal tumours.
The, potential survival can be 1 to 3 years. You know, that might involve them having a couple of courses of radiation, but a lot of dogs bearing in mind they're often You know, 8 to 10 years old when they're diagnosed, that's a very, very good outcome. I've put these in the notes, so you should have all these averages.
Brain and spinal tumours, you know, they can do very well if they're, for example, meningioma. Meningioma patients could live 3 years, even gliomas can live 1 to 2 years. Anal sex, we have lots of anal sac dogs that are still going really well, 234 years down the line.
microscopic disease, or mast cell tumours, soft tissue sarcomas, for example, they can also do a very long time, like several years. And we, you know, we see individual dogs, individual tumours. So, for example, we treated a husky with A very bad heart-based tumour quite recently, and he lived 1516 months.
You know, it's actually really good survival as a patient, you know, all the dogs with, You know, quite bad tumours, we can do really well with, radiation for these guys. So just an example of a brain tumour. So, you know, this is relatively small tumour.
This is, how much brain we used to radiates. So the red part is that we're treating at the, the very frontal olfactory lobe, and the blue is the green are the bits of radiation coming through. They're quite cold, so that's not a very high dose of radiation, because you can see we've kind of spread it.
To put the maximum dose in the tumour and the lesser dose around the normal tissue so that it shouldn't be a risk of significant side effects with that kind of blue and green doors. It's an example of a, this was a weird nasal tumour that was growing out of the dog's nose, on the dorsal part of the nasal bone. And you can see that that was before and after radiation.
So the tumour on the left is poking out. Off the top of the, nasal cavity and the tube on the right, that's after radiation. The dog was completely normal, and that dog did really well for a couple of years.
So this is an example of scar. So this is a greyhound with a mast cell tumour. The surgeons.
In the tuber first and take a picture of it. And then they take pictures of where they've been surgically. And then when it comes to us, we can use these pictures to guide us in where we treat the dog.
So the picture on the bottom right is the dog on the treatment table. Its treatment field is marked in yellow, so you can see the cross on the leg. That includes the tumour plus a few centimetres of margin.
And the thing you can see on the side is like a bless material. It helps when you've got a thin like like that, the radiation to be absorbed in the right areas and bless is the radiation to the, to the skin. So this is an example of if you were referring a dog with a, Mast cell tumour or soft tissue sarcoma, these things are really useful for us to minimise side effects, because if we receive something like this without pictures, we have to treat a much bigger area and that dog will get skin burn.
That's one of the side effects of skin radiation. So if we can minimise that, then obviously preferable. This is a cat that I treated about 4 years ago, spinal tumour.
The actual spinal cord is relatively resistant to radiation if you prescribe it carefully. A lot of people used to worry about spinal damage. The main organ I was worried about here was the heart.
You can see on the picture in the middle that, Had I not kept the beams away from the heart, there's a much more significant risk of damaging this patient's heart than there is of the spinal cord. This cat is still alive as far as I know, like 4 or 5 years later. So those are, different tumour types, and how we, mostly those are all the examples of how we treated them.
And I can talk now about the, the new technologies that we have to reduce those doses to the normal tissues and reduce the potential risk of side effects. So the machine we use is there on the left. That's the true beam linear accelerator.
The radiation comes out of the head, which is at the top, top right picture. And there's this metal thing called a multi-leaf collimator, which, we would call the MLC, which shapes the radiation beam there. So you can see that that is set.
So the computer is telling that MLC, I want you to treat this tumour, which is shaped like a bit of an oval with a bit of a banana on the side. So that's how accurate we can shape things around tumour beds. And this, is an example of a Patient with a nasal tumour being treated with, this is Comparison between IMRT and 3D.
The, the images that we use to obtain them by these equipment. So, first of all, we have a Basically, X-ray type thing. So it's called the EPI, which is an electronic portal imaging device.
And we use the radiation from the machine, from the linear accelerator. This is MV energy, not KV Energy, to take an image of the patient on the table. So, if you look there on the left, you'll see that the radiation head is over the couch, which is black.
And underneath it, there's this thing sticking out. That's the X-ray panel. And we use that mostly for bony landmarks.
So if we're treating. For example, a prostate or nose or something, it can be useful for taking a one-dimensional image, or two-dimensional images, you can take a lateral and a DV type image. And that's how it looks.
So, the top is the type of images we can take for a new machine. And the bottom is the type of images we used to get with an old machine, just to give you a comparison. So actually, treatment accuracy.
On the new machine, you can see that very clearly is way better. I mean, we were quite good at looking at these older type images on the old machine, and we could be relatively accurate, but this is where, you know, diagnostic quality of X-rays basically coming out of what is a treatment machine. So it's, it's really a game changer.
And we also, even more fancy, have an onboard CT scan on the Linac. So this is it on the sides, in the red boxes. And basically, it's a cone beam CT.
So it's not a diagnostic level. You can only treat a certain length. Sorry, you can only image a certain length of the patient.
But it's fine, like, a cat's head, you know, it's literally diagnostic quality CT. And, there's an example of the type of CT you get, and it's as good as many. Diagnostic is actually better than some of the ones we get from, older CT machines.
So we can use that to be very accurate. In imaging of patients. So here's an example of, a bladder, urethral tumour.
So you can see that these images are kind of, there's half the CT that we got from the Linac and half the CT that we did in the first place when we were planning the treatment. So, it's a planning CT superimposed on the CT that we're using for positioning. So you can see how similar they are in terms of diagnostic quality.
And it, what that allows us to do is to literally exactly match the area we want to treat. So instead of having to do, I mean, if you think back to the big, the blue, red, and pink, and the planning treatment volume, we might, we can do much, much less PTVs. We really don't need to have that margin of error anymore, which means we can treat much less of the normal tissues.
And it allows us to bring our doors to the tumour higher because we don't need to worry so much about damaging normal tissues in the treatment field. So, that was image-guided radiation, which basically is using the built-in imaging on the linear accelerator to make us target the tumours more accurately. And the built-in imaging comprises X-ray panels and CT scanners, and we use MV and KV energy to image.
So this is what I was talking about at the very beginning intensity modulated radiation. So, this is also a game changer. It's a treatment that allows us to move the radiation very, very close to the tumour and off the normal tissues.
So, historically, a dog with a nasal tumour would have had its eyes treated, and it would have got cataracts and potentially uveitis and potentially corneal ulcers. But now we can kind of paint the doors onto the tumour. So, if you look on the left picture, you can see that that's avoiding the eyes because we've told the computer, I want you to treat tuber, not eyes, for example, and it, you know, with the A nasal tuber.
That is significantly better for the patient, quality of life, for the owner's quality of life, for our quality of life, because we don't have a patient with sore eyes from having the radiation in the short term. It can also allow us to shorten the treatment time because we can give a higher dose, we can give it more quickly. And it, it's really now the standard of care.
I can't really imagine a case where I would now treat a nasal tuber with three-dimensional radiation, only if it was really palliative, because doing the plan for an IMRT does take more time, and it's slightly more expensive than a three dimensional treatment. So, yeah, if it was a very, very palliative patient because it had a life-changing comorbidity, possibly, but most of the dogs with nasal tumours now will have IMRT to minimise the side effects we used to see with older. Treatment.
And there's the comparison again, just to remind you of how much radiation there. You can see the red and orange is the treated bit, and the blue and green is the drop, the do drop off the colder areas of tissue being irradiated. And you can see how much the eyes are getting on that picture on the left in the old school and how much better it is on, on the right.
So, a step up from that is BAX, which is volume modulated radiation. And The difference between IMRT and VAT is that IMRT is the beams are static, so they start at, say, 0, and they come around to 90, and they come round to, 170, for example. Whereas this VAT is delivered in an actual arc.
So the, the head of the treatment machine moves around. The patient and the tumour. And sometimes you might do a whole arc all the way around 360 or you might do two half arcs, 180.
And that allows a lot more dynamic painting of the doors, the radiation dos onto the tumour. At the same time, the MLC that I talked about, which moves during the intensity modulated radiation, also moves during edoema. So you have a lot of movement, and the radiation is literally being more accurately painted on.
There's often not a huge difference between VMAT and IMRT in terms of the actual plan and the doors to the tumour and tissues. But sometimes it can be quite obvious. So sometimes I'll do both plan, like when I'm doing the plan, I'll just see how it looks on both and decide which one's better.
Sometimes it's to do with patient size. For example, like a long, big Great Dane or something, you might not get the arc around the patient. Because it might collide, so you, you have to do the static beams and make sure you Have them coming in at different angles, so I might here would be more appropriate.
It's faster than IRT, and when I say faster, we're talking like a minute, but that can make a difference, bearing in mind all of these patients are anaesthetized, and we might have 10 or 12 patients a day. So yeah, we still do all of these. We still do all 3D for a lot of things, palliative things.
We do IMRT for a lot of nasal tumours and VMAP, probably more commonly, for example. Anal sacs and when we're doing more complex stream of the brains, which I'll come on to now. I just wanted to show you an example of a VMAP treatment.
So if you look on the right, the image there is an old school treatment of a trigeminal nerve she tumour. You can see how much of the, the head is being treated. And the video I'm going to play now shows how it is be mapped.
So you see the radiation dose that's tracking up the nerve. That is so much. More accurate and much less normal tissues do than.
In the old example. So, way much better for the patient. And allows a higher dose to the tuber.
So, stereotactic, you may have heard people talking about stereotactic and how It's very popular because clients like it because the treatment is delivered in a much shorter time. So for a lot of the traditional IMRT and VMAC treatments, if we want to be, cautious with prescribing, and there's reasons we might need to prescribe smaller fractures more frequently, some of those patients will have 3 to 4 weeks of treatment, or at least 2. So you can imagine that's a lot for an owner to bring them for 4 weeks, or they might have to stay with us, which is not good for owners or pets.
So, If they can get stereotactic, that's great. So stereotactic is basically delivering a similar dose of radiation that you would give over the sort of 2 to 4 weeks. In 3 to 5 days, sometimes even in 1 day.
Most of the time we do something between 3 and 5. And there's very specific criteria because this is a very, very targeted treatment. So there is very, very specific criteria for stereotactic radiation.
The tumour has to be clearly defined. If it's a very diffused tumour, you're giving too high a dose of radiation to the normal tissue, and you risk having quite significant side effects. So it has to be a clearly defined tumour.
Perfect examples of things like pitu tree, some meningiomas, even some gliomas. Nasal tumours, I think we're moving more and more now that most patients will have stereotactic for a nasal tumour unless it's horribly infiltrating the skin. The subcus, for example, We, what else do we do?
Adrenals, obviously something that's quite localised. We can do breath holding. So our anaesthesia team have, got protocols for getting a patient to hold his breath so the tumour doesn't move, so that we can treat these tumours with really high accuracy.
So stereotactic is basically a definitive treatment. The aim is to give the best dose we can, the tissue very accurately. And we make a decision when we see the patient, we see the imaging if they're a candidate for stereotactic or regular radiation.
And I would say about 70, 80% of the time, we know from the presentation, occasionally we do have to change it. If we find that the tumour is more infiltrated when we image them and do the plan, and we have to say to the, I'm sorry, we can't do stereotactic, we have to do traditional. They'll often still go for it.
Obviously, for us as a treatment facility, it's way better to only have the patients in for a few days. You know, most of these patients come on Monday, go home on Friday. It's much less for the owners.
It is actually, though, much more time consuming to plan it. So because it has to be so it probably takes 2 or 34 times longer even to do a stereotactic plan and to QA plan and make sure it's super accurate. So it is.
More expensive. Some of the owners question that. Why is it more expensive for 5 days and 20 days?
Because the 20 days is just repeating the same over and over again every day, whereas this, the, the actual time it takes to plan them is really heavy, really heavy on the radiation oncologist. So another example is from one of the papers about soft tissue sarcomas. So another example of stereotactic, how accurate it can be on the tumour and How much less of the, the hot dose, the strong dose you're getting to the normal tissues.
So this is a patient of mine, Ebony, who came all the way from Hong Kong, Hong Kong, I think, to have his brain tumour treated. And she was a mess. She was circling really abnormal.
She, she made it over to us. And this was a tumour. She had, of course, stereotactic radiation.
And very frustratingly, after she stayed with us for a month or so, for a long story, but to do with the import and export, she went home, she was a lot better. And she had an MRI scan at the, referring practise in Hong Kong, but unfortunately, the imagings have been taken in a much thicker plane, so I wasn't able to get a very good picture of The resolution of her tumour, but the longer the shorter it is, her tumour had shrunk by about 30 to 50%, which is fairly normal. She was clinically much better.
The owner was a lot happier with her. So this was a really good story. And as far as I know, she's still doing well.
She was with us last June. And I would expect, you know, I said earlier that average brain tumours can live for maybe 1 to 3 years, depending on the tumour. In Ebony's case, she has a lot of comorbidities, as well as this, and it's quite a bad tumour.
So I wouldn't necessarily be so optimistic about 3 years, but hopefully she'll be OK until at least This summer, maybe a bit longer. And this is a picture of Ebony and her sister, who ironically is also called Sarah, having that her 13th birthday party, when she made it back to Hong Kong. So hopefully she's still doing well.
So she's a stereotactic patient that had treatment over 5 days. This This is an example of a nasal tumour. So this patient had nasal tumour, you can see it completely obstructing the left side of the nasal cavity.
Treated with radiation complete response, similar to the dog I showed earlier. So that can be very nice to see these patients clinically improve. For a long period of time and have good quality of life.
So, in summary from You know, the types of radiation we can do. It's much more accessible to owners now, where historically, it was always either palliative over once a week, or they have to do 12 or 15 treatments over 4 weeks. Now we can really tailor the treatment to the owner and the pets and the tumour, and give them a lot more option with much less risk than historically they had.
A lot of owners worry about repeated anaesthesia. It really isn't an issue for us. We've been doing it for years.
We have very, very rare problems. We have a specialist in anaesthesia team. They're used to doing anaesthetics for radiation, and because radiation treatment's so short, they may go on for 4 weeks, but each day is only like 5 minutes.
You know, we literally just get the patient to sleep, treat them, and wake them up. So we use short-acting drugs. And they don't suffer any of the hangovers they get with long surgeries and, and things like that.
So last but not least, I just want to talk you through how to refer for radiation because I think a lot of people just aren't really sure. They don't know what the indications are, and that, obviously, there's not many centres offer radiation. So, People may not have been exposed to it before in their career.
So often, not often, but sometimes we see patients, clients who Found out about radiation a long time after their pet was diagnosed when they Googled it, and their vet wasn't aware of it or didn't think that it was possible in that particular case. So often when you're seeing a, a client with a tumour and you think radiation may be indicated, they might go, oh, no, no, no, because it sounds too invasive and they've heard of horror stories from the past or whatever. And I think the first thing is just to ask some open questions, you know, does the client know that cancer can be treated?
You know, do they know what the likely prognosis is with different potential treatments? One of the barriers, actually, to a lot of patients having radiation is that the clients are afraid of the consults. They don't want to bring the animal all the way to find out it's hopeless, or they have these preconceived, worries.
But actually, when they find out you can do it by phone, they're quite happy, and they're quite unnamable many times to spend the money to have the discussion regardless of whether they go ahead or not. You know, most of our owners who do the consult and don't go ahead are actually super happy and they give us good feedback. So I think they just appreciate having the option, being able to talk it through with someone and then knowing they've had an informed decision.
Just on a side note, you know, if you know that a patient has, for example, a nasal tumour, you just know because it's completely obstructed or it's sneezed a bit of the tumour out, or somebody's done an X-ray already and it's got a soft tissue opacity, then It can be useful to send. To refer it for staging at the radiation centre, because that will be more cost-effective and more streamlined for the owner. I'm not suggesting you do this with every patient, of course, if you need to make a diagnostic CT in practise, that's fine.
We prefer they have a diagnostic CT in many cases, because you might find things that also need to be managed. And also, if we're doing the planning CT, that can take quite a lot of time. And not having to stage it at the same time is useful.
If you're not sure, then it's worth, asking us. You know, for example, if you know a Great Dane has an osteosarcoma and you're not sure whether it needs a CT or not, you know, just ask the radiation oncologist, what do you think? And we'll always be happy to talk you through it to get the best outcome for you, for the owner, for the animal.
Again, just a reminder of all the things that we have to consider. These are not so many things for you to consider, but why it's easier for us to spend the time going through all the options with the order than it is for you, because you will not know what dose or fractionation we want to give to the patient. And some vets, you know, are used, were trained in back in, you know, 1015 years ago, and they're like, oh, yeah, all the radiation centres just give 4 treatments or 12 treatments, and the owner will say, I don't want that.
Whereas actually now, we have all these new options, all these different schedules that we can do. So just to basically give that to the owners, say, look, you know, they might just give you one treatment, they might give you 20 but they will talk you through every single option and do what you, you know, make a decision together. It's all about contextualised care, and not about us telling them this is what we do.
When you do refer, or when your nurse or receptionist does the referral, it's actually really important that we have, the following, which is Original reports, any pathology, bloods, anything like that. For the, for us as oncologists, we care most about the pathology report. We use that to plan the treatment.
So something that may not be of concern to the local vet, for example, potentially a slightly narrow border or something to the tumour or some infiltration might be really important for us. So we do like to see those rather than having some of it copied and pasted into the history. And our anaesthesia team wants to see the clean path.
They want to see the biochemistry and the haematology actual results, not just it was all OK kind of thing. When we can, and nowadays with phones, tumour photographs, photographs of the tumour on the patient, surgical photographs, they can all really help us be more accurate in treating the patients. Of course, having the history is useful.
Any previous referral reports from other centres, if the dog's gonna have its leg irradiated and it's had a TPLO, that kind of stuff, we need to know. And we really need the DICO imaging study. So if you have done a CT or an MRI or even radiographs in practise, we need to see the original images.
Because that is the biggest deciding factor for us in the conversation we have with the clients. So we need to see those before the consult, ideally, a few days before the consult, not on the morning. And if we can have all that together, it's also really helpful, because our reception team spend a lot of time gathering bits and bobs of information on, on all different emails on different days, and sometimes we end up with something missing, and then they have to call your practise again, and then your receptionist has to do it when they're busy.
And just having it all together in like a package is really helpful for streamlining the process for the clients as well, because then we can get them booked in faster. So, that was probably an awful lot to go through in an hour. And, you may well have questions, which I'm willing to take via, or my team are willing to take via email.
So, you know, we're always available for advice. Basically, in summary, you know, we can treat most tumours with radiation, some with more definitive and some with more palliative intent. It's A relatively straightforward process for us, but there's a lot of complexity in how we decide what treatment we give.
I would not like to have to write a SOP, for example, I mean, we have, we do have some protocols, we treat all brains. Over 5 days, we treat all nasals over 3 days, for example. The stereotactic, but we still will deviate from those in different situations.
For example, an animal that doesn't tolerate anaesthesia well, or, whatever. So, yeah, a lot of the things we treat, we have a lot of, flexibility on the prescription. Basically, it's not.
You know, like omeprazole 1 week cake or something like that. And there are a lot more modern techniques now that make radiation safer, better, more accurate, more available, and owners will be able to find out about by Googling and going to information that, is available on the internet. So I hope that that helps.
As I say, anything you want to ask, you can email the team on oncology at Southfields.co.uk.
And I hope the notes are useful as well. Thank you very much for your time.