Breast cancer drug cuts risk by 50%

But at what cost?
10 November 2023

Interview with 

Liz O’Riordan


Breast cancer awareness pink ribbon


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.



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