DCIS - ductal carcinoma in situ

If you have ductal carcinoma in situ (DCIS), it means that cells inside some of the ducts of your breast have started to turn into cancer cells. These cells are all contained inside the ducts and have not started to spread into the surrounding breast tissue. So, there is very little chance that any of the cells have spread to the lymph nodes or elsewhere in the body. Doctors use various terms to describe DCIS, including pre invasive, non invasive, or intraductal cancer.

Your doctor may describe DCIS as a very early form of breast cancer. If it is not treated, in some women DCIS starts to spread into the surrounding breast tissue after some years. So it may become an invasive cancer. DCIS is being found more often because it is sometimes picked up by mammograms when women are screened for breast cancer. About 4650 women are diagnosed with DCIS in Great Britain each year.

DCIS and invasive ductal breast cancer are not the same thing. In invasive ductal breast cancer, the cells have broken out of the ducts and there is then a chance they can spread into nearby lymph nodes or other parts of the body.

Surgery is the main treatment for DCIS. Many women have removal of the area of DCIS, with a border of healthy tissue around it. This is called wide local excision or conservative surgery. After wide local excision surgery, you usually have radiotherapy to the rest of the breast tissue. This is to kill off any abnormal cells left behind. Your doctor will discuss with you the possible benefits and risks of radiotherapy.

Some women have mastectomy (removal of the whole breast). They don't then need to have radiotherapy. If you want to, you can choose to have breast reconstruction after mastectomy. You may be advised to have a mastectomy if

• The area of the DCIS in your breast is large
• There are several areas of DCIS in your breast
• You have small breasts and too much of the breast is affected by DCIS to make wide local excision possible

Some women prefer to have the whole breast removed rather than wide local excision as it makes them feel more confident that the DCIS is cured.

If your DCIS cells have oestrogen receptors, your doctor will usually suggest that you have tamoxifen (a type of hormone therapy) to try to reduce the risk of developing an invasive breast cancer in the future. Doctors are still researching how well tamoxifen and other hormone treatments work in stopping DCIS from coming back. Some trial results suggest that tamoxifen may not give much extra protection if you've already had radiotherapy. You can find information about research into treatments for DCIS on our clinical trials database.

There are now ways of classifying DCIS into high grade (more quickly growing) and low grade (more slowly growing). There is also an intermediate grade, that is in between high grade and low grade. Doctors think that the high grade DCIS is more likely to spread into the surrounding breast tissue and more likely to come back after treatment. This way of classifying DCIS may help doctors to design trials, and find out more about how different grades should be treated.

Whichever treatment you have, you will have regular follow up appointments to make sure that if DCIS comes back in the treated breast it is picked up as quickly as possible. Your specialist will probably suggest mammograms at least every 2 years. If your DCIS does come back, your specialist will probably suggest that you have a mastectomy.

The IBIS 2 prevention trial aims to find out if the hormone therapy anastrozole (Arimidex) can help to prevent breast cancer or DCIS in women who are at high risk of developing it. The IBIS II DCIS trial is currently comparing tamoxifen with anastrozole to see which works best at stopping DCIS coming back after surgery. Anastrozole is a type of hormone therapy called an aromatase inhibitor. 

The FORUM trial is testing whether a type of internal radiotherapy (brachytherapy) works as well as conventional radiotherapy for DCIS and breast cancer.

There is detailed information about trials for DCIS on our clinical trials database. Type 'DCIS' into the free text search box.