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Macmillan and Cancerbackup merged in 2008. Together we provide free, high quality information for people affected by cancer through our publications, website and phone service. Find out more| .
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This information is about ductal carcinoma in situ (DCIS). It should ideally be read with our general information about breast cancer| .
DCIS stands for ductal carcinoma in situ. Most breast cancers start in the cells that line the ducts (the channels in the breast that carry milk to the nipple). DCIS means that there are cancer cells lining the ducts, but these are completely contained (in situ) within the ducts. The cells have not spread into the surrounding breast tissue or anywhere else in the body.
DCIS usually affects a localised area of the breast, but the area affected can be large. It rarely affects different areas of the breast at the same time. Sometimes, DCIS is described as pre-cancerous, pre-invasive, non-invasive or intraductal cancer.
The structure of the breast
If DCIS isn't treated, it may, over a period of years, spread into (invade) the breast tissue surrounding the ducts. It is then known as invasive breast cancer. Not every woman with DCIS will go on to develop breast cancer if it is left untreated, but it isn't possible to predict when DCIS will develop into breast cancer. So although DCIS isn't harmful, it should be treated.
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.
The exact causes of DCIS are unknown. The risk factors for developing DCIS are similar to those for invasive breast cancer. Certain women appear to be at a higher risk, including:
Most women with DCIS have no signs or symptoms, and only know they have DCIS when it is seen on a mammogram. Because more women are having mammograms as part of the national breast screening| programme, DCIS is diagnosed much more frequently than it was in the past. 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's important to remember that most micro-calcification is not DCIS or cancer. A small number of women with DCIS may have symptoms, such as a breast lump, fluid coming out of the nipple (discharge), or an eczema-like change in the nipple.
If an abnormal area is found on the mammogram, the doctor takes a sample of tissue (biopsy) from this area so that it can be examined under a microscope. The biopsy is carried out using a special needle called a core biopsy needle. Your doctor will give you a local anaesthetic to numb the area before the biopsy is taken.
If there is no obvious lump, mammograms are used to ensure that the sample of tissue is taken from the correct area. Alternatively, the radiologist may insert a wire into the abnormal area to guide the surgeon so that the correct piece of tissue can be removed. This is called wire localisation biopsy. A local anaesthetic is given to numb the area before this procedure is carried out.
The treatment for DCIS depends on its extent (how much of the breast is affected) and its grade.
The most important treatment is surgery to remove of all the affected breast tissue, together with an area (margin) of normal breast tissue around it. This is done to make sure all the DCIS is removed. This operation is called a wide local excision| (WLE), and it's carried out under a genderal anaesthetic.
If the area of DCIS is large, or affects more than one area of your breast, your surgeon may advise that you have the whole of your breast removed (mastectomy| ). For most women losing a breast is very distressing and your surgeon will explain to you why this operation is the best treatment for you. Your surgeon and breast care nurse will also discuss breast reconstruction| (an operation to form a new breast) with you. Sometimes this is done at the same time as the mastectomy. Occasionally some women choose to have a mastectomy because it feels like the right decision for them. Mastectomy cures the condition in virtually all women, and often no further treatment is necessary.
Some women with DCIS may have the lymph nodes (sometimes called glands) under their arm checked. This is done to make sure that there isn’t an area of invasive cancer within the DCIS which has spread to the lymph nodes. If you’re having a mastectomy you may be advised to have a test called a sentinel lymph node biopsy| . This is a way of checking just one or two of the lymph nodes under your arm to see if they contain cancer.
Radiotherapy| uses high-energy x-rays to destroy the abnormal cells while doing as little harm as possible to normal cells. Women who have high-grade DCIS are often given radiotherapy after their surgery. This is because doctors think that high-grade DCIS is more likely to come back and radiotherapy can help to reduce this risk. Women with low-grade DCIS don't usually need radiotherapy. Radiotherapy is normally given every weekday for 3–6 weeks.
Sometimes, the cancer cells within the area of DCIS have receptors for the female hormone oestrogen on their surface (known as oestrogen-receptor-positive DCIS). This means that the cells rely on the hormone oestrogen to grow. Tamoxifen| , an anti-oestrogen drug, is sometimes given to women with oestrogen-receptor-positive DCIS to try to stop DCIS from coming back after surgery. But it's not clear how effective tamoxifen is in DCIS, and there are ongoing research trials comparing different hormonal therapy drugs to tamoxifen.
After surgery to remove the area of the breast affected by DCIS (wide local excision) there’s a small risk of DCIS coming back in the remaining breast tissue. You will be offered yearly follow-up appointments and mammograms. This means that if the DCIS comes back it’s detected as early as possible. Mastectomy is likely to be the chosen treatment if the DCIS comes back. Breast reconstruction| can be done at the same time.
All women who have had DCIS will be offered a yearly mammogram of the unaffected breast. So if you’ve had a mastectomy you’ll still need to have a yearly mammogram.
If you notice any changes in your breast or in the unaffected breast between appointments, you can arrange to see your breast cancer specialist earlier.
Research into treatments for DCIS is ongoing, and advances are constantly being made. Cancer doctors useclinical trials| to assess new treatments. Before any trial is allowed to take place, an ethics committee must have approved it, and agreed that the trial is in the interest of patients.
If you are asked to take part in a clinical trial your doctor must discuss the treatment with you so that you have a full understanding of the trial, and what it involves. You may decide not to take part or withdraw from a trial at any stage. You will then receive the best standard treatment available.
You may be asked to take part in a trial called IBIS II – DCIS, which is comparing the hormonal therapy tamoxifen with a different type of hormonal therapy called anastrozole (Arimidex®).
You may experience many different emotions| , including anger, resentment, guilt, anxiety and fear. These are all normal reactions, and are part of the process many people go through in trying to come to terms with their illness.
Some women find it helpful to talk things over with their doctor or nurse. Close friends and family members can also offer support.
This section has been compiled using information from a number of reliable sources, including:
Early and locally advanced breast cancer diagnosis and treatment. 2009. National Institute for Health and Clinical Excellence (NICE).
Improving Outcomes In Breast Cancer – The Research Evidence. 2002. National Institute for Health and Clinical Excellence (NICE).
Eds Souhami et al. Oxford Textbook of Oncology. 2 nd edition. 2002. Oxford University Press.
Souhami and Tobias. Cancer and Its Management. 5 th edition. 2005. Oxford Blackwell Scientific Publications.
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