Ductal Carcinoma in Situ (DCIS)

What is ductal carcinoma in situ (DCIS)?

DCIS stands for ductal carcinoma in situ. This means the cancer cells are inside the milk ducts or ‘in situ’ (in place) and have not developed the ability to spread either within or outside the breast. DCIS is an early form of breast cancer and may be described as a pre-invasive, non-invasive or intraductal cancer. It may affect just one area of the breast, but can be more widespread and affect different areas at the same time.

A doctor explains what DCIS is.

A doctor explains what DCIS is.

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What is DCIS and what’s all the uncertainty around it because women often find it quite a difficult thing to understand?
 
I think it probably sounds more difficult with the technical language that is used because the use of words, for example Latin terms that are not in everyday use, so therefore it’s not surprising that people think that there must be a great deal to it, and it’s very intimidating.
 
I think if we initially consider how the breast is made, then it gives us a better chance to understand what DCIS itself is about.
 
The way the breast is structured, there are areas within the breast where the milk is made, and then small tubes, milk ducts as such, that drain from those areas towards the nipple. So that the milk produced can go towards the nipple. Those tubes are milk ducts, they will have cells that line them so they will be called ductal cells, and the vast majority of breast cancers occur in those ductal cells. Those ductal cells lose the normal constraints that they have as regards their behaviour and their growth and they get out of control and therefore are cancerous. And what “ductal carcinoma” means is a cancer of those ducts and the “in situ” bit means in one place.
 
So the cancer change in those cells lining the ducts has occurred but it hasn’t broken through the lining just outside of that layer of cells. And the significance of that is that those cells can’t migrate to any other part of the body, so that’s the big issue with DCIS, it’s a local phenomenon. It is a form of cancer, although some ladies prefer to look at it as “pre-cancer,” thinking that cancer as such is where cells migrate to other parts. 
 
And I suppose one of the words as well that sometimes causes distress is “invasive.” And often cancers as such are described as invasive cancers. If one was being technically correct, in common everyday usage we tend to drop the word invasive because it does seem to express something much more aggressive, whereas it’s only saying, well this is a cancer. Ductal Carcinoma in situ is not invasive. It hasn’t reached a stage where the cells have broken through the lining that contains them, and therefore it hasn’t got the ability, even if it wanted to, to go into other parts. So that is really the essence of DCIS.
 
Right, that’s very clearly explained. Some women feel confused by all the different terms such as “pre-cancerous,” “pre-invasive,” “non-invasive,”
 
Yes. It is unfortunately a continuing situation where many different terms are used to try and explain something. And all of them are very similar. Patients often struggle even with benign and malignant, thinking that benign is some form of cancer as well but may be less aggressive.
 
In the simplest way, I think it’s easier to divide lumps, which would be a common thing, into being benign or malignant, and malignant and cancer would mean the same thing, and benign would mean everything that isn’t a cancer. So those two broad categories.
 
Again I must stress that patients shouldn’t be put off by the jargon. The DCIS is, they’re entering a whole new world of medical jargon and therefore stand back a little and understand it as a form of breast cancer where the survival in the future is excellent. And that some of them would have developed proper breast cancer, but quite some time in the future often, so there’s no need to feel that there is an urgency, or that they need to rush into something. They can take their time and understand things, and understand their treatments and then progress.
 
For most cancers, we see, including breast cancer contrary to popular belief they develope slowly and they change slowly, but people are seen very quickly, and for good reason, because of the upset. In an appempt in order that people are not delayed everything moves at pace and sometime patients then get the impression that things must be changing quickly and I must be in great danger at this time. They are not, they can draw back slightly and say this is whats happened I need to understand it a bit more and then they will make the treatment choices that are best for them.
If DCIS is left untreated, it may, over a period of years, spread into (invade) the breast tissue surrounding the ducts. It is then known as invasive breast cancer. DCIS is not harmful in itself, but it is usually treated to prevent it developing into an invasive breast cancer. Not every woman with DCIS will go on to develop breast cancer if it is left untreated, but it is not possible to predict reliably which women with DCIS will go on to develop invasive breast cancer. Doctors haven’t yet reached a consensus about the nature of this disease and its management, although research is underway to inform this such as the LORIS trial - a trial comparing sugery with active monitoring for low risk DCIS (see Cancer Research UK for more information).

Treatment, usually surgical removal of the affected area(s) of the breast, aims to prevent the development of invasive cancer. For most women this will mean removing only a small part of the breast (lumpectomy or wide local excision). However, about four out of ten women (40%) diagnosed with DCIS in the UK have their whole breast removed (mastectomy) because more than one part of the breast is affected (Thornton H, Edwards A, Baum M. Women need better information about routine mammography. BMJ 2003;327'101-3).

More information about wide local excision and mastectomy can be found on Macmillan Cancer Support's website.

A doctor explains why DCIS is treated by either wide local excision or mastectomy.

A doctor explains why DCIS is treated by either wide local excision or mastectomy.

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A lot of women wondered why some of them were treated by wide local excision and others by mastectomy.
 
Yes. It is quite a shock to patients isn’t it, that you can have something where everybody says your future outlook, your prognosis, is ever so good; your survival should be very good, but then in the next sentence suggest that you need a breast removed to achieve that.
 
And even for, if we call them “ordinary cancers,” in other words invasive cancers, the type of surgery or the extent of surgery that is done is not related to how aggressive the cancer is. It is related to its width. And again, in very straightforward terms, what the surgery is trying to do is to remove everything that’s cancerous. So if that area that is cancerous is a narrow piece, then taking a piece of the breast will be adequate. If the cancer change in your breast extends over a wide area, then removing a piece won’t achieve removal of all the cancer, nor will it allow afterwards a good cosmetic outcome for the patient because so much of it would have been removed that the breast wouldn’t look right.
 
So people can still have a wonderful outlook and survival in the future but need a mastectomy now because their cancer is wider than a piece or wide excision, as it’s called, would allow.
 
Some women, after reading a bit more, also wondered if they were being over treated if they had a mastectomy for DCIS.
 
The mastectomy, as we were mentioning earlier, is to solve the straightforward question that any patient would say, “I’ve had my operation, have you removed everything that was wrong within the breast?” And if you can do that by taking a piece of the breast, conservation surgery as it’s called, then you’ve achieved your goal. But if it’s over a wide area, then you need to remove all of the area that’s abnormal and that may mean a mastectomy. And there isn’t a way around that, you can’t, if you like, just take part of the area that’s wrong and reassure patients that that’s been enough. Because it won’t be of benefit to them.
 
So the mastectomy, the surgical option is based very much on the width of the tumour. The over treatment therefore as in how a patient balances the loss of their breast compared to the worry, would they develop cancer in the future that would shorten their life, is ever so difficult, because none of us really can say from one patient how they’re going to progress or what’s going to happen to them over time. Everyone varies slightly and it’s a very good question, it’s the crystal ball saying, “What’s going to happen to me in the future?” And none of us have the ability to be able to predict that.
 
Yes. And some women who really were shocked and distressed at the thought of having a mastectomy wondered whether they could take hormone therapy instead of having surgery, and just be monitored by mammographic screening every year say.
 
Yes, if we again take that from it’s start in the sense that we are presuming that that lady has only DCIS to begin with, and therefore we assume that the picture we have on the x-ray is giving us the full information, which it will in many instances, but there maybe some of those patients who already have some invasion and therefore already have some invasive cancer. So we are categorising them all the same from the start, without being able to say for certain that that is the case.
 
The role for anti-hormonal tablet treatment, the best of which or the most well known of which is tamoxifen, is usually when you’ve had the abnormal area removed, and you’re trying to prevent a further cancer occurrence in that breast or even a brand new one happening in the opposite breast in the future. There isn’t a great deal of information that if you treat the DCIS in the breast without any operation and just give the patient tamoxifen, as to how effective that will be, and the problem for the patient is they want you to be able to do something just at the moment when they think something’s gone wrong. So at the moment that things are becoming invasive is when they’d want you to do more. And we have no way of measuring that, you would have to wait for example till they develop a lump or a mass on the x-ray, at that stage say you now have an invasive cancer and therefore you do need more done. And they may still do very well in the future, but their outcome would be slightly less favourable because they’ve now developed a lump and they may feel they’ve missed a great chance at an earlier stage of having it cured with treatment.

And a lot of women also wondered why the different, in different hospitals women seemed to get treated in different ways for DCIS.

I suppose part of that is how people present, and every patient is different. And sometimes ladies will say, “I didn’t quite have that treatment, but this lady had a different treatment,” and that’s how it should be because I know there are a number of ways of treating somebody, many of which would be effective for different reasons. And the treatment the patient gets should be specific for them; it should be for the problem that they’ve come with. Much like we said earlier, some patients would have a small piece of the breast removed, others would have a mastectomy with a reconstruction because it was over a wider area.

So every lady’s treatment will differ, be it DCIS or be it invasive cancer. Now it is true that people then look on things differently from a clinician point of view and, as we said earlier, when you have a situation where the evidence isn’t cast iron that an extra treatment of radiotherapy or tamoxifen is always of use. And people have different beliefs as regards to the benefits that patients get, so there will be some variation.

 And have you come across many women who didn’t want to have any treatment at all?

Very few actually, in essence, and we often say to patients that, for example when a lady goes to a breast screening unit for her mammogram, most will go in the belief that they’re going to be told that everything’s alright. They don’t go really thinking that this process may well find something that’s severe. They’ll think about it when the question’s asked, but the normal way of things to go is to be told they’re alright, it’s not part of the plan to be told that maybe things aren’t alright.  And therefore patients when they come usually feel that something’s been found and it needs to be dealt with. Now they have the information, the diagnosis, it’s very difficult then not to do something about it. If they didn’t know, they would be alright. But once they know, they find it very difficult to ignore.

There are three grades of DCIS: low, intermediate, and high. The grade relates to how the cells look under the microscope, and gives an idea of how quickly the cells may develop into an invasive cancer (or how likely it is that the DCIS will come back after surgery). Low-grade DCIS has the lowest risk of developing into an invasive cancer, and high-grade carries the greatest risk.

A doctor explains more about the different grades of DCIS.

A doctor explains more about the different grades of DCIS.

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And when do doctors usually know the grade of DCIS?
 
They’ll have a suggestion from the small pieces done by the biopsy, when the patient is first diagnosed. And you’ll have an impression that it’s DCIS because on the mammogram, which is now how most are diagnosed, there’ll be the absence of any “mass” as the jargon calls it. In other words, the equivalent of a lump, there will just be change in the mammogram without any ‘mass’ or lump on the mammogram. And with that type of change the expert radiologist will often say, “It looks as if there could be cancer change in the breast, and if there is, it’s likely to be DCIS.” They’ll then proceed to do a biopsy taking small pieces for the x-ray department, and when they’re looked at under the microscope, the pathologist would be able to say, “Yes there is cancer change, and yes it does look like DCIS, and the type of DCIS that I see looks high grade.” So you’d have a good idea at that stage, but we wouldn’t know for certain until the piece has been fully removed and then analysed under the microscope.
 
And women also asked about the different grades of DCIS. And whether low grade over time progresses to high grade? Could you talk a bit about that?
 
Yes. There’s two aspects to that I suppose and again they are very sensible and valid questions. The first is, we don’t know exactly what it is that is in the breast until the pathologist has fully examined all of that change. And the only way the pathologist can examine it is if it is removed. Everything else is a best estimate, based on the x-ray, and based on the biopsy. But you don’t know for certain what the cancer change in that breast is, if it’s all DCIS or if there’s little areas of invasion, or if the DCIS is high or intermediate or low grade, till it’s all been fully examined. So we are very dependent on the situation where you have it removed to have the best category put on it.
 
Now the natural history of DCIS will vary from person to person. Some will go on and develop a proper or invasive cancer as it’s called in that area of DCIS. But others won’t, and we’ll never know at what stage of evolution the patient has come. They may have had it for 15 years or 10 years or 3 years or 6 months. And therefore we don’t know where they are on that road and the rate of change in it with invasive cancer you cannot say from one individual.
 
You do know with high-grade DCIS that there is an increased chance of a breast cancer being present there at the start, in small areas the invasive we spoke about earlier, or it developing in the future. Or even the DCIS coming back or recurring in that breast in the future.
 
With the low grade it’s probably much slower, more indolent, and whether it’ll really ever cause harm to that patient longer term, or shorten their life, is very doubtful. The difficulty is knowing that all they have is low grade because, as we said, you don’t know that for certain until the thing has been removed.
Most women with DCIS have no signs or symptoms and only know they have it when it is seen on a mammogram. This is why DCIS has been diagnosed more frequently since three-yearly breast screening for women aged 50-70 was introduced by the UK National Health Service (NHS). The NHS Breast Screening Programme is being gradually extended in England to women aged 47 to 49, as well as to those aged 71 to 73 as part of a Trial.

DCIS usually shows up on a mammogram as an area where tiny specks of calcium have collected in the breast ducts, known as micro-calcification. It is important to remember that most micro-calcification is not DCIS or cancer. A few women with DCIS, however, do have symptoms, such as a breast lump, fluid (discharge) coming out of the nipple, or a type of rash involving the nipple called Paget’s disease (see Diagnostic mammograms).

In the UK, non-invasive cancers such as DCIS about 3 in every 200 women screened, this adds up to about 4,000 women each year in the UK (NHS Breast screening programme July 2016). Only one of the women we spoke with had ever heard of DCIS before her own diagnosis. Many were unsure as to whether it was actually cancerous or not. Most wanted more information about DCIS and felt unprepared for the diagnosis because they’d had no symptoms. With hindsight, a few women wondered if they had actually had a symptom but one which hadn’t been noticeable enough for them to visit their GP.

Sue had not heard of DCIS before her own diagnosis.

Sue had not heard of DCIS before her own diagnosis.

Age at interview: 50
Sex: Female
Age at diagnosis: 49
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DCIS was something I’d never heard of before. Different friends had had different sorts of breast cancers but never this DCIS. And what he [doctor] explained was that some of the biopsies they’d taken showed that they were cancerous. But the others were benign.
 
I took my husband with me that day because I knew I could get not the result I wanted. And I needed somebody with me. When the doctor told me that yes it was, the cancer was in the milk ducts, it was contained and non malignant, he said it was the best sort of cancer to get. It did make me think ok. But at the end of the day I just said to him, “Ok that’s fine.” Which is … it wasn’t really fine. But that’s just what … you’re just in shock when they tell you that you have something like that.
 
But I had a wonderful breast care nurse there who I then went talk to afterwards. And she explained everything about DCIS. DCIS was something that obviously I’d never heard of before. And she gave me lots of literature. She told me go onto the breast cancer website.

Pam had only come across DCIS because her mother was diagnosed with it several years earlier.

Pam had only come across DCIS because her mother was diagnosed with it several years earlier.

Age at interview: 55
Sex: Female
Age at diagnosis: 53
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My mum had breast cancer when she was eighty-three. She’s now ninety-two this year. So hers was diagnosed initially as DCIS. And to cut a very long story short, when they took a biopsy, when they sent all that material off, they found that it had actually broken through into her breast. So therefore it was breast cancer, two very tiny areas of breast cancer.
 
So she had a lumpectomy. But she hadn’t actually got a lump. She had the lumpectomy, had a small area taken away. That’s the tissue that they looked at and that’s when they discovered that it had actually gone that bit further. So because of her age and because she didn’t want to be having radiotherapy, chemotherapy, whatever, they told her, she opted to have a mastectomy because of her age. And that was done and she didn’t have to have any follow-up tablets or any chemo or radiotherapy. None of that. So I actually looked into DCIS quite a bit for my mum because at that point in time I had nothing wrong with me.
 
How old were you at that time, if you don’t mind me asking?
 
Oh I can’t remember my age now but mum was, if you can do the maths, my mum was eighty-three. She’s now, well ninety-one. She’ll be ninety-two this year. And I’m fifty-six this year. So I’ll leave you to do the maths on that because I’m hopeless [laughs].
 
But obviously I was concerned and wanted to learn more about DCIS for my mum’s sake. Because we were hoping she wouldn’t lose the breast and also I did ask the nurses at the time, should I be concerned and my sister, I’ve got an older sister. I was told that there no greater chance of me getting it or my sister getting it than any other woman getting so we shouldn’t be concerned about that, because my mum had got it later on in life. Had she got it before she was 50 then, you know, we might have been looking at a family link. So that was what was said. These were doctors and nurses in [place name] because that’s where I’m from originally, that’s where my mum still lives. So this was all done at the hospital in [hospital name].
 
So I already knew a fair bit about DCIS because I asked my mother’s doctors and nurses, I read the posters, I picked up leaflets and, you know, I looked into it, as I say, from my sister’s and my point of view. So that all happened for my mum.

Ann wondered if she'd had symptoms but had pushed them to the back of her mind. She thought she'd have a lump if there was anything wrong.

Ann wondered if she'd had symptoms but had pushed them to the back of her mind. She thought she'd have a lump if there was anything wrong.

Age at interview: 58
Sex: Female
Age at diagnosis: 56
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I’ve tried to think back. I’ve said, “Am I really kidding myself that there was nothing that I suspected about how my breast was?” And I suppose I have to, you know, again maybe I’m trying to convince myself but if I’m totally honest I had been going to the doctor about, what, a sort of tightness across my …. And I always said, “Oh, I’ve got the … you know, family would say, “You’ve got an awful cough mum. You know, why don’t you go and sort it out?” And I had been a couple of times and in the end she’d sent me for an x-ray to look at my chest. They found nothing. Given me an asthma test, they could find nothing. But there was always this feeling of tightness across there.
 
And also I think, well as I said, my father was ill but I’d lost my mother in 2003. And that was quite difficult as well because, as I say, they were miles away. But my sister and I shared it between us. But I do remember when she was ill getting some slight panic attacks and feeling that there was something pressing on my, deep down inside me. But I didn’t used to worry about it. I thought, “Oh it’s, I don’t know, indigestion or something like that, you know.” And it used to come and go and, as I say, I suppose my life at the time was so, I had so many things to think about that I think, and I thought I was getting older, maybe this was just old age, you know, something that explains …. But I suppose, looking back, maybe there was something there. But I genuinely had never ever thought it was anything to do with my breasts. And, as I say, I had been to the doctor a couple of times and we’d never sort of gone down that thing at all.
 
So, you know, I had no lumps as such. But it did seem to be getting a little bit heavy, my boob. So maybe there was something there. But that’s in retro, you know, looking back on it. And, as I say, I’ve spoken to so many of my friends and they’ve never heard of DCIS. You know, if you read anything it’s all about lumps and bumps and things like that.
 
But it still feels very, it still feels very dramatic to me, that you go in with, not even, maybe you have, maybe I did have something but I certainly hadn’t acknowledged it. And I don’t think it was because I was consciously pushing it to the back, how you might do if you found a lump maybe. I really, that was quite genuine. So the whole thing, you know, I found it quite tough I suppose.
See the 'Resources' section for a list of resources related to DCIS.
 

Last reviewed July 2017.

Last updated July 2017.

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