Breast cancer drug breakthrough, and hibernating hedgehogs

Plus, a guide to the upcoming COP28 summit
10 November 2023
Presented by Chris Smith


Hedgehog outdoors


In this edition of The Naked Scientists, the drug called Anastrozole can help prevent thousands of cases of breast cancer among older women: but at what cost? Also, climate change expert Mark Maslin on what we need to know about the forthcoming COP28 summit kicking off soon in Dubai. And, how the UK’s hedgehogs have been going through a rough patch...

In this episode

Breast cancer awareness pink ribbon

Breast cancer drug cuts risk by 50%
Liz O’Riordan

Tens of thousands of post-menopausal women in England could benefit from a drug that helps prevent breast cancer. The disease is the most common cancer in the UK, and anastrozole has been used to treat it for decades. But the drug has now also been licensed as a preventative option. NHS England’s national clinical director for cancer, Professor Peter Johnson, told the BBC that it was a major development:

Peter Johnson - It reduces the chances of breast cancer developing by about a half, which is obviously really quite striking. That's about 290,000 people between the ages of 50 and 69 in this country. If even only about a quarter of those people do it, we will see 2000 fewer cases of breast cancer as a result of that, so that's very attractive.

So, how much of a game-changer is this announcement for those who are susceptible to breast cancer? And what cost might accompany this mass medication? Liz O’Riordan is a breast cancer surgeon and also developed the disease herself at the age of 40…

Liz - The biggest risks for getting breast cancer are being a woman and getting older; it is mainly a disease of older women. One in seven women will get it in their lifetime, but about one in 800 men will get it too. We do know it is happening in younger women in their twenties, thirties and forties and we don't know why. However, we are very good at treating it these days. Two thirds of women and men diagnosed with breast cancer will go on to live a long and healthy life and won't die of it. Sadly, about 20 or 30% of women and men do get breast cancer that comes back and can't be cured, but we are getting more and more treatments to delay that happening.

Chris - And the announcement that's been made this week, where does that fit into the picture and what's its impact?

Liz - For a while we've been looking at a way to stop women getting breast cancer to stop them going through this devastating illness like I have, and also to save the NHS money. A new drug called anastrozole, which is used to treat breast cancer, has been shown that it can stop some women getting breast cancer in the first place.

Chris - How does that work?

Liz - Most breast cancers are stimulated by a sex hormone called oestrogen. The cells have receptors on their surface and, when oestrogen locks onto them, it makes them grow and divide. Anastrozole is a class of drug that stops your body making oestrogen after the menopause. So, for women in their fifties and sixties. That means you naturally don't have any oestrogen, so any breast cancer cells that are starting to wake up don't continue to grow and spread and form a cancer.

Chris - So who would it be used for? Who would benefit from this finding that we can perhaps reduce the risk of breast cancer even further?

Liz - So this drug is available to women after the menopause, and they need to have a moderate or a high risk of getting breast cancer - more than double that of a healthy woman. That basically means you have at least two relatives who've had breast cancer and they need to be close to you; a mum, a sister, an aunt, or a gran.

Chris - Would this be a lifelong regimen, then? You would start taking this and just never stop?

Liz - No. The trial showed that you only take it for five years and that's how long most women with breast cancer take it because there are serious side effects of not having any oestrogen at all.

Chris - And what sorts of side effects can people expect?

Liz - So most of you listening will have heard of the menopause, but because this drug stops you making any oestrogen at all, the side effects are worse. So there's things like hot flushes and night sweats - my mum needs to go into the freezer aisle of the supermarket to cool down. It also makes your bones and your muscles ache; you can feel very stiff. It can drop someone's sex drive and it can also weaken your bones because oestrogen naturally strengthens your bones. Without it, you're at a greater risk of breaking your bone if you were to fall over.

Chris - So in this study, they found that women who were at high risk, who took this drug for the five years you're saying, they reduced their risk of getting breast cancer in the years they had during the follow-up?

Liz - It wasn't quite that dramatic. It was actually small numbers that were affected. They realised that they had to give 30 women the drug to stop one woman getting breast cancer. So 29 women took it for five years and it didn't have any impact on their outcome.

Chris - The argument that was made was that when one tots it up on a cost basis, the cost of treating a case of breast cancer is far greater than the cost of giving those 30 women this drug. But you are arguing that doesn't take into account the fact there are going to be 29 women who would remain healthy, but are subject now to those side effects?

Liz - I think the drug is now off licence, so it's much cheaper to give, and one tablet is much cheaper than potentially giving women surgery, chemotherapy, radiotherapy and drugs for life. But it doesn't take into account the extra tablets they may need to stop them thinning their bones and the impact of the side effects on their quality of life. And in the study, a quarter of the women didn't complete the trial because they couldn't tolerate the side effects of the drug.

Chris - Where does this leave us, then? Because it sounded like great fanfare when this was announced this week. Obviously it is important if we can identify who the people most at risk are. Is it a question of just making an even better judgement about who we intervene with to push that 30 we need to treat down to a smaller number? Or are we just going to have to live with the fact that we are going to have to subject a fairly big group of people to a lot of symptoms, risks and side effects to save each case of breast cancer?

Liz - I think that's where we are at the moment. Although molecular medicine is making a huge impact on how we treat people with breast cancer at the moment, there is no way of knowing if a healthy person will develop it or not. So it does come down to, if you have a higher risk than the general population, you may think it's worth taking this tablet in the hope that it stops you getting breast cancer. But you need to know there may be side effects available and you can't have hormone replacement therapy to help with those. But I would also say the three biggest things you can do to reduce the risk of getting breast cancer and many other cancers are boring: things like exercising every day, not drinking a lot of alcohol and trying to keep your weight down. They've been shown to halve the risk of breast cancer developing and they're free.

Chris - And how are you getting on now because you have a pretty dramatic story. You're very young - much younger than the average age onset for a person with breast cancer - and you've also had recurrences.

Liz - I have. I first had breast cancer age 40, and then it came back at 43 and then it came back again as a nodule on my mastectomy scar earlier this year before my memoir launched, actually, the day before. But I'm doing all right. I now have bum injections in each cheek once a month and I'm on a different tablet to hopefully stop it coming back a third time.

Chris - And coping with the side effects of this ongoing suppression therapy. Is that okay?

Liz - It's not fun. It's like a very mild dose of chemo that I have every day; I feel very tired, my tongue is very sore and everything tastes different. But you don't mind putting up with the side effects because you hope it's going to stop you getting breast cancer again. That's very different to a healthy woman taking something that will make her feel miserable that might not work.


The nighttime skyline of Dubai, featuring the Burj Khalifa.

What to expect from COP28
Mark Maslin, UCL

Soon, the 28th annual United Nations climate meeting will kick off in Dubai, in the United Arab Emirates. It follows a year of extreme weather events in which many climate records have been broken. So, what should we expect from COP28? Mark Maslin is a professor of earth system science at University College London and the author of 'How to Save Our Planet: The Facts.'

Mark - The COP meetings are where a huge number of people get together every year and it's sort of like the end of the negotiation process. So the climate change negotiations are going on all year round and this is just the jamboree at the end to try and actually get agreement and push the agenda forward. And people don't realise that COP is actually really complicated. So you have this small inner circle, which is the negotiators for about 196 countries and they're the ones trying to work on the wording and the actual agreements that are going to come out. Then round that, you have what's called the blue zone, and these are all organisations who are involved in the negotiations. So this is like the World Bank, the world food agencies, and also things like, there's a youth pavilion, there's an indigenous peoples pavilion. Then outside that you have the whole business community that turn up because they know that they're going to have all these organisations, all these negotiators there at the same time as them. And so they have business to business meetings. And then if it's in particular countries, then you have civil society and it's a huge, I would say, melting pot of ideas, but also lots of negotiations going on within the actual negotiations, but also outside.

Chris - What are they actually negotiating?

Mark - So what they're trying to negotiate is how the world moves forward. How do we actually decarbonise, how do we reduce all those greenhouse emissions and how do we do it in an equitable way? The whole of the negotiations are on that path to net zero. We are now in a new era of negotiations where it's not if we're going to do this, it's when we're going to do this.

Chris - Is it actually happening though, or is it all just hot air? Because I keep hearing all these promises and then I hear that more promises are coming and then we'll see more headlines saying that what we agreed in Paris, well that's gone and we've already broken that particular target. That's history. So have they actually got teeth into these agreements and if so, what does that involve?

Mark - Really what these international negotiations do is set the agenda. So the most important one was in Paris in 2015 where there was an agreement by all countries that we were going to hit net zero in the middle of this century. And the most important thing is that it came with a target. It said, look, we will try to keep climate change to just two degrees, but we have an aspirational target of one and a half degrees. This has driven global economics, it's driven countries and how they put in policies. So the huge growth in renewables that we see around the world is driven in part by this top down sort of approach.

Chris - I read a quite poignant piece someone had written the other day in which they say the amount that China will increase its output this year is more than if the UK went net zero tomorrow. In other words, they are eclipsing just the increase in their emissions, our entire carbon footprint annually, and they're not the only ones. Obviously India, America, and it's increasing. Now is everybody signed up to do this or are we going to be in a position where they're very virtuous countries impoverished themselves and beggar their economies and actually achieves net nothing for them?

Mark - So the first thing to take away is that 90% of the world's GDP is currently under a pledge for net zero. The United States, Europe, and the United Kingdom will go net zero by 2050. China has said 2060 and India 2070, but this whole China excuse many countries in the western world had this huge legacy. We have been burning fossil fuels since the 1880s, okay, when the industrial revolution really took off. And so many countries have a long legacy. So what we're doing now isn't huge compared with what we've done in the past. So there's a historic legacy, but the interesting thing is we've moved past that as a global community. It is just now not who's going to go quickest. It's like we all have to go net zero and can we actually push other countries to do it?

Chris - But China and India, that's a third of the world's population and if we allow them extra leeway, then since they're accounting for the lion's share of the output between them, are we not really ignoring the elephant in the room?

Mark - Well, so India has a really good comeback to that, and they turned around and said, if everybody lived like an average Indian person now there would be no climate crisis. So we have to be very careful because individually, if we look at the amount that we as individuals in the UK actually produce per person as a society, it's much higher than a person in India and much higher than a person in China. So there's this idea of equity, but we're all on the same process. We're all going the same way. And of course, are we going to try and push China and India to decarbonise as quickly as possible? Absolutely. But the other thing that people forget is that if we are going to do it, we are going to be the ones with the technology. We're the ones that are going to save all that money because what we don't really get across to people is now we really invested in renewable energy 10 years ago. The cost of living crisis that everybody's suffering from now wouldn't have affected us because it's a lot more efficient, it's a lot cleaner. We get less air pollution and it's cheaper.

Chris - Solar panels aren't cheap, Mark.

Mark - So the energy that is produced from solar panels is a lot cheaper. So huge solar farms, offshore wind is a lot cheaper than actually gas and gas produced electricity. And the interesting thing is that you are talking about individuals, and this is where many of us would disagree with the politics, which is why should the individual person have to pay for solar panels? We didn't have to pay for the gas grid. So why do we have to pay for the solar panels on our house, which are going to produce electricity, which we're going to sell back to the grid. So there's an interesting, I would say, separation here about what is good for the country and should be funded and what's being put onto the individual.

Chris - Are there any controversies around the fact that that cop is going to be happening in Dubai this year?

Mark - Oh, this is a massive controversy. So we are going to be in the United Arab Emirates, one of the biggest oil and gas producers. The president of COP is also the CEO of the United Arab Emirates Oil and Gas National company. And he has declared that they're going to double their production of oil and gas by 2030 at the same time as chairing a meeting where we are all on that pathway to net zero. Huge controversy. But the interesting thing is, is that going to help? Because we have to get the oil and gas nations on board. We have to be able to persuade countries like the UEA, like Russia, like Saudi Arabia, that they need to decarbonise and they also need to reduce the supply of oil and gas because we're going to be using less of it in the future.

Chris - So how's that going to go down?

Mark - I have no idea. And this is interesting because having talked to lots and lots of regular goers to COP meetings, people that actually understand the geopolitics, we have no idea what's going to happen at this COP. Strangely enough, in Glasgow, I had a really good idea what the British government and the Italian government were going to do. I had a really good understanding of how the Egyptians were going to play it. This, I don't think we can call it. Again, maybe it's just a staging post. Maybe it'll be a talking shop and we don't get any new agreement. Or maybe because of the actual idea about national pride. This is the United Arab Emirates actually going, right, we're going to help the world decarbonise. We're going to lead the world into a new state of negotiations. So it's interesting how this politics plays out.

The International Space Station (ISS)

25 years of the International Space Station
Ed Bloomer, Royal Museums Greenwich

This month marks a quarter of a century since the International Space Station was sent into orbit. It’s a remarkable achievement, but we’re not sure what will become of the vast structure. The space agency NASA hasn’t ruled out keeping it in operation beyond 2030, but it looks far more likely that the ISS will be decommissioned and sent hurtling to a watery end in the Pacific Ocean. James Tytko went along to the Royal Observatory in Greenwich to meet their senior astronomer, Ed Bloomer.

Ed - 25 years is a long time. What it has become is our permanently occupied space lab. It's able to run a huge number of different projects, different experiments, and it's also a sign of international collaboration and co-development.

James - Almost unique international collaboration in the domain of science.

Ed - Yeah, I think that's correct. As I say, permanent occupation for about 25 years from different space agencies, members of different countries, many of whom have not been getting on, let's say, politically during that time. The international collaboration is absolutely necessary to run the place: it has to happen regardless of what else is going on. I think there's something interesting in that.

James - We better expand a bit on what a space station actually is. You mentioned it being our permanent home up there, but it's got more of a function than that, hasn't it?

Ed - The conditions are completely inhospitable to human life normally, so you have to construct something specifically to survive there, to remain there. It's not the first space station. I think, off the top of my head, ISS is the ninth one with occupation and it's got lots of different things that go on all the time within it. Not just the stuff that the astronauts are conducting personally but experiments on the astronauts themselves to see what effect space life has on the human body is a big part of it as well.

James - Is it those sorts of astrobiology learnings that you'd say have been one of the hallmarks of the work that's gone on, on the ISS?

Ed - I mean, there's other things, like we have a potential dark matter detector on there - hard particle physics. But certainly, life sciences, seeing how plants grow, seeing how cells develop, seeing how the astronauts bodies themselves... keeping them under basically constant monitoring. Yeah, I would agree that life science is a big part of it.

James - Because there's some discussion to be had, I think, that whether it's been a good use of resources or not comes down to this idea of whether humans in space is really a happy marriage in the first place and whether we're forcing a square peg into a bit of a round hole here. With the hundreds of billions of dollars worth of investment that's gone into the ISS, how do you view those quiet voices of descent which are starting to grow a bit louder as the space station comes towards the end of its life and people are looking at it retrospectively?

Ed - It's a big question. You're right, it's an inhospitable environment and humans are not naturally built for it. We're not naturally built for lots of things that we end up conquering, so I think there's definitely a spirit of investigation and figuring out what it takes and some of that will end up with some hard answers about what we can do, what we can't do, how much we would have to change ourselves to live on Mars or live on the Moon. There's big questions to be asked there. I think when we talk about costs, the money generally speaking is used here on Earth. You use up fuel, rocket fuel is pretty expensive, but the majority of the cost is about the development of industry here on Earth and that has all sorts of spinoff applications and tangential relationships. This gets discussed when we talk about things like the Apollo Moon programme. As a function of the time, it was very expensive, but the amount of stuff that came from it, the development of technology that came from it, means that we live in the space age anyway; personal computers, the glass on your mobile phone. It's not like we're chucking a crate of dollar bills and throwing them out the airlock. It doesn't really work like that.

James - As we are looking back at the 25 years it's been up there, we're also looking forward to the ISS being decommissioned in 2031. What's that as a result of?

Ed - So unfortunately nothing lasts forever and complicated machinery, though you can repair, eventually gets to a stage where it's perilous to keep it going for longer. Safety is a big concern and, in general, you wouldn't be surprised if your car of 25 years had an occasional breakdown or if you're still trying to use a laptop 25 years later. Now they don't exactly compare, but at some point you've got to have a plan for decommissioning this stuff. They can't just go on forever.

James - But presumably this is not the end of space stations as we know them? There will be ones that supersede it? What are the plans to replace the ISS? Do we need to?

Ed - Well, that's a complicated question and I think different space agencies around the world have different answers to that. Roscosmos has a plan for a third generation Russian space station. The Chinese Space Agency has all sorts of plans for permanent occupation. So the interesting question I think maybe is, do we get something similar again or do different space agencies only go their own way or do we have different partnerships? Certainly, I think there's still ambition for occupation in space, but whether there is consensus and the funding and all the rest of it that you would need for ISS version two, that's not clear at this stage.

Hedgehog outdoors

24:02 - How to help hedgehogs hibernate

How climate change is affecting our prickly friends

How to help hedgehogs hibernate
Hugh Warwick, British Hedgehog Preservation Society

November can be a particularly prickly time for hedgehogs in the UK as they dodge fireworks party bonfires and prepare for hibernation. But this year, their plans to sleep through the winter have been disturbed by both unseasonably warm weather and heavy flooding in large parts of the country. It’s meant that rescue centres have been inundated with referrals. So, what should we know about hedgehogs and how we can help them? Hugh Warwick is an author, ecologist and a spokesperson for the British Hedgehog Preservation Society.

Hugh - The UK's only spiny prickly mammal has made this fantastic compromise. They've lost the great insulating fur of other similar sized animals like rabbits and things. And they've got this defensive coat, which is great for many things, but it doesn't provide that warm coat which helps survive the colder weather. And so what you've ended up with is, they need to find a way of surviving through a time when their food, which is insects, invertebrates, and that sort of thing, is not readily available. And they do that by shutting themselves down. They go into hibernation. And the problem this presents the hedgehog is that they are uniquely vulnerable at this time. And the challenge that they face is getting enough fat reserves stored up so that they can cope with a time of inactivity over the colder months.

Chris - How do they reproduce? I suppose the stock answer is carefully, but how do they?

Hugh - So hedgehog courtship is a wonderful thing. It involves a lot of snuffling around, and as I do a lot of talks to the wonderful groups like the Women's Institute, and I have to point out that mating cannot take place while a female frowns, which always generates quite a degree of hilarity. So they're famous for rolling up into a ball when they're frightened. But the first thing a hedgehog does is it frowns and that frown muscle extends from above the nose down to the tail, and it brings a spines up in a sort of prickly jagged mess. So an upset female mating cannot take place. Once the male has circled and circled and circled a receptive female, she will relax and that will allow mating to take place,

Chris - <laugh>. And when do they do that? When's reproduction and when is this hibernation period for them?

Hugh - So where are we now? We're recording this on the 6th of November. Around this time of year, the hedgehogs are looking for somewhere to hibernate. Between November and March. In March they begin to emerge from hibernation. And by April they tend to be out and about snuffling and courting. And then mating will take place from that moment onwards.

Chris - Do they come out at all during that hibernation or is it literally one long sleep?

Hugh - So researchers found our hedgehogs will arise from hibernation throughout this winter period, and in fact, sometimes they'll change their nests during that time as well. So it's not a completely continual sleep pattern. The hedgehogs further north, which you can find up in Norway, will tend to go into hibernation and it tends to be a bit more of a 'it's pretty cold out there, we'll stay in this until spring comes.' Whereas here where we've got longer wetter winters, which can be at times quite mild, they can be stimulated out of hibernation.

Chris - And is that the problem we've got at the moment? The fact we've got a lot of groundwater and this is flushing them out of their homes in some cases.

Hugh - Groundwater is a problem when there's lying water and there's flooding because a hedgehog in hibernation will drown if it's covered in water. It's been very mild. So hedgehogs will probably only be beginning to think about going into hibernation. I think one of the issues is that the mildness is keeping hedgehogs awake longer than they would anticipate. And so you end up with quite small individuals being found at this time of year. We know that a hedgehog weighing less than 450 grams won't survive hibernation. And so people are finding these ones out and about and when you get sudden storms, we've had lots of rain of late, that will displace hedgehogs from day nests. It will get them up and about and then they'll be seen tottering around the garden looking like they may be a bit drunk. And that just means they've got hypothermia and they are on their way to death unless somebody intervenes.

Chris - And what can the average person do in their own grounds around their own home if they know there are hedgehogs active there to help them out?

Hugh - What it boils down to is don't be so tidy in your garden. If you really want to help hedgehogs, make sure there's vegetation, make sure there are piles of leaves. Make sure there's a log pile, make sure there's a bramble patch. Make sure there's a compost heap. All of these sorts of things provide structures in which hedgehogs can make a really good nest and they provide a lader of food. On a bigger picture, if you really want to help hedgehogs, I would suggest looking at changing the way we grow food, changing our transport infrastructure, altering the national planning policy framework and possibly looking to dismantle industrial capitalism. But those can all be a little out of the reach of most people and their gardens. So maybe start with getting your garden a little bit more untidy before moving on to societal change.

Chris - Are there any mega no no's? Because I do hear people say it's terrible to do what some people do and put things like milk and that kind of stuff down. This is not good.

Hugh - Hedgehogs have a reputation for enjoying drinking milk, and this comes from years and years and years of people doing that. And hedgehogs will drink milk. The trouble is hedgehogs are lactose intolerant and that they don't know that they're lactose intolerant. And so it can give them an upset tummy. Hedgehogs are carnivores, their favourite food throughout the year. Worms, beetles, caterpillars and insects, all sorts of things. And if you want to help them with food, kitten kibble is actually one of the easiest things to give them. And in dry spells lots and lots of water as well.

A marble

What is the magnification of a marble?

James Tytko took on this question with the help of Richard Bowman from the University of Glasgow...

Richard - Thanks James. A clear marble will act as a lens – because the glass slows down the light that travels through it, it will bend light whenever it passes through the surface at an angle. This is known as refraction.

James - To calculate the optical magnification effect of the marble, we need to find out the focal length of the lens. This is the distance at which the light passing through the marble converges to a single point.

Richard - For that, we need to consider the radius of curvature of the marble and its refractive index (which measures how much light gets slowed down by the glass.) A typical marble made of normal glass will slow light down by about a factor of 1.5, and it might have a diameter of perhaps 12mm.

James - If you carefully trace the rays of light as they get bent on the way into and out of the marble, you come up with a focal length that’s a function of both the refractive index and the size, and for the numbers Richard mentioned that gives an effective focal length of 9mm. That means that you could hold the marble next to your eye, and be able to focus on an object only 9mm away.

Richard - The “magnification” this gives you is a surprisingly tricky concept: technically, the ratio of the marble’s focal length to the focal length of your eye sets how much bigger the image on your retina is than the object. However, this isn’t how we normally define magnification: you’re used to looking at objects quite a long way away, and most microscopes define magnification relative to looking at an object about 25cm from your eye (as you might do when reading).

James - That means the magnification will be the ratio of the focal length (9mm) to this distance (250mm) which suggests you have a magnification of about 28x – enough that you could easily see the pixels in a typical screen. If you use a smaller marble it scales linearly – so a 6mm marble would give you twice the magnification.

Richard - You’re right that scientists have known this for centuries – indeed the first microscopes were just small glass balls, and by using small ones (only a few millimetres) early scientists were already able to see microscopic features like cells: indeed the name “cell” came from the appearance of plant cells, which the observer thought resembled the cells in a monastery.

James - What a wonderful piece of trivia. Many thanks to the second to Nun, Richard Bowman from the University of Glasgow.

Thanks to Richard Bowman for the answer!


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