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Ductal Carcinoma In Situ (DCIS)
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How DCIS is treated

Treatment for DCIS usually involves surgery, either a lumpectomy or mastectomy, to remove the abnormal cells.

After surgery, you may also need radiation treatment or hormone therapy.

Surgery

The purpose of the surgery is to:

  1. Remove all of the DCIS.
  2. Allow the pathologist to look at the abnormal cells that are removed during the surgery.
    • The pathologist will measure the size of the DCIS and make sure that there is no breast cancer in the tissue.
    • They will also make sure that there is an edge of healthy cells around the removed tissues (clear margins). This is important as it means the surgeon was able to remove all of the DCIS.

A lumpectomy removes only a portion of the breast where the DCIS is located plus some healthy cells around it (the margins). After a lumpectomy, most patients will be offered radiation (high energy x-ray) treatment to the breast to help reduce the risk of the DCIS returning or the risk of breast cancer developing.

A mastectomy removes all the breast tissue. A mastectomy may be recommended if the DCIS is in more than one part of the breast or covers a large area of the breast. You may also choose to have a mastectomy if you are unable to have radiation treatment for other reasons. You may be able to have breast reconstruction at the same time as your mastectomy. Your cancer surgeon can help to connect you with a plastic surgeon who will assess if you are a candidate.

There is a slightly higher chance that the disease will return with a lumpectomy, but with careful monitoring, the survival rates for women who have a mastectomy or a lumpectomy are the same.

Your surgeon will help you decide which option is best for you based on: 

  • The amount of abnormal cells in your breast 
  • Your breast size 
  • Any treatments you had in the past 
  • Your genetic risk of getting breast cancer

You may need a second surgery if:

  1. There is DCIS near the tissue at the edge of the lumpectomy (positive margins). This can sometimes happen if the DCIS is larger than the imaging shows. When this happens, your surgeon may be concerned that there is some DCIS left in the breast and will recommend a second surgery.
  2. There is a small cancer in the DCIS. The surgeon may have to look at your lymph nodes to make sure that the cancer has not spread.

Your surgeon will give you more information if a second surgery is needed.

After surgery

After surgery, you may need more treatment: 

1. Radiation treatment

  • Most of the time, if you have had a lumpectomy, you will also receive radiation therapy afterwards. Radiation therapy will help lower the chance of the DCIS coming back. It will also lower the chance of you getting breast cancer.
  • If you have had a mastectomy, most likely you will not need radiation therapy afterwards. While uncommon, you may need radiation if the DCIS is very large or it is close to the margins.

2. Hormonal therapy (or endocrine therapy)

  • Sometimes, your doctor may recommend taking Tamoxifen (brand name: Nolvadex, Soltamox). Tamoxifen can lower your risk of developing a new breast cancer in the other or same breast and reduce the likelihood of the DCIS coming back.