Debate on breast cancer screening contributing to drop in mortality

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Published: 30 Mar 2012
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Prof Fiona Gilbert - University of Cambridge, UK

Prof Fiona Gilbert discusses the current debate regarding efficacy of breast cancer screening, the low number of women being screened and the evidence in favour of mammography screening after treatment.

 

Prof Gilbert also discusses the benefits of different screening methods such as tomography and mammography.

8th European Breast Cancer Conference - March 21 - 24, Vienna

 

Debate on breast cancer screening contributing to drop in mortality

 

Professor Fiona Gilbert - University of Cambridge, UK

 

 

Professor Fiona Gilbert, we’ll not talk of what’s happened in the last 35 years since we worked together. You’ve just come out of a very extended session on breast cancer screening, and the discussion really did go on and on, didn’t it? I mean really lots to talk about. And you’re the doyenne of the subject in the UK, so, what’s happening in screening, why are you talking so much?

 

It’s a hugely interesting debate that’s going on at the moment. People have looked at the published trials, and then the existing evidence that’s coming out from different countries who are doing screening, to look and see what the impact of screening is. The argument is that it’s actually the treatment effects, the improvement in treatment has caused the decrease in breast cancer mortality; and the screeners are saying that actually, no, there is a contribution that screening has made. And the camps are polarised because there’s one camp that’s saying actually screening has had virtually no benefit at all; everyone acknowledges breast cancer mortality has decreased, probably due to excellent or incremental improvements in adjuvant treatment. So the screening doubters say there is no reduction in mortality due to screening and those that are screening advocates say oh yes, screening has made a contribution. And so it comes down to how, and it’s all the same data that’s being analysed, which is the fascinating thing, and it’s how the different statisticians and epidemiologists look at the data, I was going to say choose to look at the data, but it’s how they actually approach the data. So in the session that we’ve just had it was hugely interesting, because people like Richard Peto was saying that one of the groups had taken what he felt was the wrong risk of patients getting breast cancer.

 

Without screening?

 

Without screening.

 

Which was 0.3%, whereas in the UK it is proven to be 2%,

 

That’s right. And although he was taking a wider age range, because it’s actually 1% between, say, 55 and 69, but if you take a wider age range it’s 2%, and then you get the bigger…

 

And then the peak of the curve is of course at the right hand side.

 

Exactly.

 

Where do you sit in this, Fiona? Because you’re at the front line, you’re doing screening every day.

 

Well I’m somebody that was appointed into a screening job when the screening programme started, I set up screening in the northeast of Scotland, I’m still doing breast screening, and I suppose stepping back from it all, you’re looking at what is the logic, what is it we’re trying to do? We’re trying to pick up aggressive grade 2 or grade 3 cancers at a very early stage, before they have metastasised, or at a stage where the tumour burden is such that any adjuvant treatment will… you know, the immune system will be able to mop up the cells. And I suppose the most recent work that we’ve done is looking at people who have had breast cancer, who then continue to get mammographic surveillance annually. And we’ve shown that in fact if you can pick up the second event, either the recurrence or the second primary, when it’s small, less than a centimetre, or even less than two centimetres, then the survival is improved. And we went back to the UK cancer registries and showed that. And the only way to pick up a cancer less than a centimetre in size is by a screening test, is by a mammography or by MRI or probably not ultrasound and clinical examination.

 

So I think the logic is still there for screening, I think it’s logical that if we can detect disease early, when it’s small, before it’s metastasised or before there’s a significant amount of metastasis, then we will impact on survival. But then there’s this huge issue about over-diagnosis and yes, small cancers which are a very low grade are likely never to kill somebody, and so we shouldn’t be treating them aggressively. And in fact there’s probably going to be a big UK trial looking at low-grade DCIS, which will randomise people to no treatment at all. So literally, women are given the diagnosis, that’ll be difficult, in a way that hopefully doesn’t frighten them, and they would accept just being in watchful waiting, and get regular imaging. And they will be compared with people who get the normal treatment of excision plus radiotherapy.

 

What will MRI have to do to break into the mammography area? Come down in cost.

 

Absolutely, MRI is a fantastic tool. But it’s a long examination, women are in the magnet for 20 minutes, they’re face down, they don’t like it, they get an injection in their arm. If we can avoid giving them intravenous contrast that would be good, it reduces the cost; if we can reduce the time in the magnet that would help; if we have dedicated breast MR machines, again that would help, because it means we can improve that the throughput of patients through the machine, so that might well be helpful.

 

You don’t think something like spiral CT but in MRI might take you another step further? Because spiral CT has been really incredibly interesting.

 

Oh spiral CT has been phenomenal in the way that we can now scan the whole body in 15 seconds. But the problem is the radiation dose with CT, and we just have to be careful about what we’re doing with that. And people are doing spiral MRI, there’s more innovative ways of acquiring the MR data, which is really interesting. There’s things like tomography, so taking a series of x-rays instead of a straight mammogram where you take one single picture, you take like 15 or 20 views, and that’s looking really promising. It looks like we get better cancer detection with the tomography technique. So again that’s another area that we shouldn’t ignore.

 

As a sort of simple jobbing doctor, I commute from Bristol to Milan each week and in Milan our early breast cancer patients do rather well, 90% of them are alive and free of disease ten years on.

 

Yes, which is very impressive.

 

I cannot say the same about the place I take off from in order to get to Milan, in the southwest of England. And that’s an issue that I have which makes me think that whichever way you get at the early patients, they are the ones who are going to live the longest and probably be cured. And so how we get there is a very crucial discussion and a very crucial decision to make.

 

Absolutely, and in the UK it’s still only about just over 70% of women accept the invitation to come and be screened. What we need to do is we need to ensure that people are well-informed and make a choice as to whether they’re coming or not, but try and facilitate that information for them. And so we have to be a bit honest about what the benefits and the potential harm of screening is, but make sure that women do come if they want to. And I think there are many other factors that influence whether you’re still alive and well at ten years and I don’t think it’s just the breast cancer early diagnosis and treatment, I think there are other lifestyle factors.

 

Well as a medical oncologist I dare to say that the surgeon’s quite important because one thing we have in Milan is sixteen breast cancer consultant surgeons and five plastic surgeons. And there’s no shadow of doubt that the quality of care is superb. And I think the surgeons still cure the most people, even for all this expensive fancy chemotherapy that I use.

 

I think that’s absolutely right. I think the surgery… I think the initial treatment is critical, and I think it needs to happen fast. I think there needs to be excellent pathology and people have to ensure that the margins are really clear, if not they need to go back. But I think the quality of the surgery is really, really important. In the UK there’s been a transformation in how cancers are treated because of the multidisciplinary teams, and that’s really important that each case is discussed by the expert group, and also that the quality of information, the quality of the recording of the data and the standards that are being given to the woman is also monitored routinely, I think that’s really important. So I think in the UK there’s been a step change, I think the improvements have continued across the UK. What I do think we need to do is continue to improve, to make sure that wherever we can across the UK that the best information is being used, that we don’t just all come down to a kind of mediocre level, that we make sure that we’re all operating at as high a level as possible.

 

It’s important for people who are not in the UK watching this interview to realise that actually some of the end points in the UK’s cancer battle are not actually quite as good as across the channel, and that’s why we’re emphasising the UK getting better to get to that level.

 

Absolutely right.

 

Fiona thank you very much this has been so enjoyable.

 

Thank you, it’s a pleasure to see you again.