DCIS - ductal carcinoma in situ

• A quick guide to what's on this page
• What DCIS is
• Treatment for DCIS
• Treatment and DCIS grade
• Follow up
• DCIS trials

If you have ductal cancer 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 becoming more common because it sometimes found by mammograms when women are screened for breast cancer.

Remember that 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.

In the past, the recommended treatment for DCIS was nearly always mastectomy. This cures virtually all cases of DCIS because all the affected tissue is removed before an invasive cancer has a chance to develop.

Now most surgeons remove only the area of DCIS, with a border of healthy tissue around it. This is called wide local excision or conservative surgery. After surgery, you should be offered 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.

You might have tamoxifen (a type of hormone therapy) to try to reduce the risk of developing an invasive breast cancer in the future. But doctors don't know yet exactly how well tamoxifen works in stopping DCIS from coming back. Trial results suggest that tamoxifen may not give much extra protection if you've already had radiotherapy. Your specialist may still prescribe it for you if the DCIS cells are likely to respond to oestrogen. There is ongoing research into hormone therapy for DCIS.

If you want to, you can choose to have a mastectomy and possibly breast reconstruction. Some women prefer to have this treatment as it makes them feel more confident that the DCIS is cured. 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

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 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. There is more information about this trial on our clinical trials database. Type DCIS into the free text search box. Another trial called the ERISAC trial looked at treating DCIS with a different aromatase inhibitor, called exemestane. This trial is now closed and we are waiting for the results.