Ductal Carcinoma in Situ (DCIS)
Diagnostic tests: mammogram
After having a routine mammogram on the NHS Breast Screening Programme, most women will receive a results letter about two weeks later. About 96 per cent of women have a normal result from their first mammogram and will be invited for screening again three years later. About four in every 100 women screened, though, are called back for further tests because of an abnormality seen on the mammogram (NHS Breast Screening leaflet May 2017).
Many of the women we spoke with said they had more mammograms when they were recalled, sometimes taken by the same radiographer who had taken the original one at the breast screening unit. Mammogram(s) taken at the assessment clinic may be at different angles or with magnification.
A doctor explains why more mammograms might be taken at the breast clinic.
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Some of the women we interviewed said that after they had their first mammogram at the screening unit, they were then recalled to the hospital because they needed more mammograms. Why might they need more mammograms?
The screening mammograms are literally a basic screening test. So they may show abnormalities but we cannot be sure in many cases from just looking at the basic screening mammograms exactly what the nature of the abnormality is. And so in order to investigate it further, we need to do further tests and we do those at a screening assessment clinic where the tests will depend on the nature of the abnormality that’s been seen.
Most women said that, at this stage, they didn’t feel particularly anxious. Several assumed they had moved when the x-rays were taken at the breast screening unit and that there must have been technical problems. A few women, though, felt daunted by needing another mammogram because they found them painful. One of these women, who was extremely worried when recalled for further tests, felt that the décor of the x-ray room should be more calming and ‘less clinical’ because women were often very anxious at this time. More experiences of having mammograms can be found on the Healthtalk Breast Screening site.
Some women said the doctor showed them their original x-ray and the areas that were causing concern. A few were shown the x-ray they’d had taken three years earlier and how it compared to the most recent one. Several women noted that the doctor used words such as calcifications, micro-calcifications, calcium deposits and chalk when explaining what was causing concern.
Carol was shown an area of micro-calcifications and told that those cells were precancerous.
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Then I got the recall, and it was one of those things where you thought, “Yeah, this one doesn’t feel quite the same.” And initially you don’t know if that's just your reaction to the recall or whether you were actually feeling that there was something there. There was no lump or anything. Went along for the second mammogram and they actually showed me the x-rays and this area of micro-calcifications, explained what that was and said they were like precancerous cells but they were in situ and they’ve not got the ability to spread and move. And at that point you know very little about DCIS. And it's not something that you've heard of, you've heard of breast cancer, of lumps, benign lumps and malignant lumps, and it's all a bit confusing. But you just keep telling yourself, “Oh this is really early, this is really early.”
Breast calcifications are small areas of calcium in the breast. They cannot be felt and can only be detected on a mammogram. Calcifications are very common and, in most cases, harmless. There are two types, macro-calcifications and micro-calcifications.
A doctor explains what calcifications are.
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It sounds very strange to be told that there’s calcium in the breast seen on a mammogram. We’re all used to knowing about calcium in our bones for example. But in fact calcium can be deposited in virtually every soft tissue part of the body, including the breast.
Calcium deposits on mammograms are a very, very frequent normal finding. So we probably see bits of calcium on routine mammograms in about a third of the cases that we look at. In most cases it is due to entirely benign normal ageing processes, for example calcification in the wall of arteries, which most people will have heard of. Sometimes calcium in tiny cystic changes, those will be very common findings.
When the calcium has a certain appearance however, it may indicate that there is some more serious disease in the breast and it can be the very first sign that we can find on mammograms that there is a cancer developing. The cancer may be inside the milk ducts, and then it is called Ductal Carcinoma in Situ, and what we’re seeing on the mammogram is the calcium deposits which are formed literally inside the little milk ducts.
Sometimes, it can mean that there is an invasive cancer present. That’s not something that we’re able to actually see on the mammogram if calcium is the only sign, and that’s something that will be seen down the microscope when we look at tissue.
A doctor discusses what a normal breast x-ray looks like.
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This is a normal mammogram and this would be the same examination in terms of the number of pictures done, whether it was a screening mammogram or whether it was a diagnostic mammogram done in the breast clinic.
And we take two sideways pictures and two top to bottom pictures. So this is the sideways image of the right breast, the left breast, and then the top to bottom pictures of the right breast and the left breast. And what we see on the mammograms is two main different types of tissue. The whiter tissue you see here and here is the active glandular tissue of the breast, and the darker tissue you can see here and here is the normal fatty tissue of the breast.
And what happens in everybody is that when they are young, most of the breast tissue consists of the active glandular tissue and therefore looks white on a mammogram, and with increasing age more of the breast tissue is fatty and there is less of the glandular tissue. So that means that in a young woman, lets say in her twenties the mammogram is unlikely to be helpful because most of the tissue will be white. And, in contrast, in a woman, a more elderly woman in her seventies for example, most of the breast tissue will be dark and fatty, and therefore it will be much easier for us to see abnormalities.
Most abnormalities, whether they are cancers or not cancers, show up as a white area on the mammogram. So that you could, you can understand why if there is a white lump it may be completely impossible to see it if it’s within the white tissue.
Also on this normal mammogram you can see, I hope, some rounded very white areas like so, like so, and these are bits of calcification, we call these macro-calcifications, they are very common normal findings and are not indicative of any sort of disease at all.
A doctor talks about breast x-rays that show abnormal calcifications.
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This is an example of a mammogram taken during the assessment process in a lady who’s been recalled because of micro-calcification. This is a magnified view so that we can really see the bits of calcium as clearly as we can, and the bits of calcium that we’re looking at are these little white dots just in this area of the breast, and we’ll usually look at these using a magnifying glass so that we can see them as clearly as we possibly can.
And by analysing the shape and the appearance of the bits of calcification we can give an indication as to whether it is likely to be due to some malignant disease, possibly Ductal Carcinoma in Situ, or whether it’s due to completely benign disease.
When the calcium looks like this, in just one part of the breast, and the little bits of calcium slightly vary in shape and form, we know that there is a risk that this is due to Ductal Carcinoma in Situ. However, we can’t be sure of that just by looking at the appearance of the calcification itself, and this is where a biopsy is necessary in order to obtain tissue so that we can look at the cells and the tissue very carefully down the microscope, and that will enable us to give a definite diagnosis.
If this is Ductal Carcinoma in Situ, when we’ve taken the biopsy and looked at the tissue under the microscope, we would then of course be discussing the appropriate form of treatment.
A doctor talks about breast x-rays that show invasive breast cancer.
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So for cases of micro-calcification where the calcification is in Ductal Carcinoma in Situ we don’t know unfortunately by looking at the x-ray whether an invasive tumour is present at the same time or not. And we may only know that once the area has been removed at surgery and has all of the tissue has been looked at carefully under the microscope.
This is an example of a screening mammogram showing a very tiny cancer, exactly the sort of cancer that we want to pick up in screening practice. These are the sideways pictures, and what we’re looking at is this little area here, which is separate from the glandular tissue, this white tissue that we see on both sides, and when we look at this really closely we can see that it’s got a slightly irregular outline and that’s pretty typical for a tiny invasive cancer.
These are the sideways pictures from a screening examination, it’s the right breast, this is the left breast, and in this case there is a little abnormal area here, which subsequent assessments showed was due to a cancer, and this just illustrates the difficulty that there is in interpreting screening mammograms because its quite difficult to pick this area out as different from some of the other white areas, as being abnormal.
One woman said that, when she had a mammogram at recall, she suspected she might have DCIS because her mother had been diagnosed with it several years earlier. Another was asked to come back for another mammogram in six months' time because the doctor was concerned that there could be a problem developing.
Seeing the x-ray convinced Janet that something could be wrong even though she had no lumps and...
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I was going for the screening every three years in the Sainsbury’s car park in the van, mammogramming, which I dreaded and almost didn’t go sometimes because I thought “oh, there’s no breast cancer in my family.” And I just felt it was the last thing that would happen to me. So I was pretty shocked when, let me think, late 50’s I suppose I was, yes, it was late 50’s when they called me back and showed me on the x-ray that there were things that looked like grains of salt. And they said it could be a pre-cancer condition or it could be calcification due to old age. So go away and forget it for the six months and come back again, which I did.
And much to my horror there were many more grains of salt on the next x-ray which, because I couldn’t believe that I would get cancer, but that convinced me. Seeing the x-rays was very helpful to convince me that actually there was something wrong because I couldn’t, I felt fine. No lump or anything.
Last reviewed July 2017.
Last updated July 2017.