Ductal carcinoma in situ (DCIS)

What is DCIS?

DCIS is a very early form of breast cancer. The cancer cells are in the milk ducts of the breast and have not spread to the outside breast tissue. DCIS is a non-invasive cancer. 

If DCIS is left untreated, the cells may spread from the ducts into the surrounding breast tissue and become an invasive cancer.

Both women and men can get DCIS, but it is very rare in men.

Are there different types of DCIS?

DCIS can be divided into:

• High-grade DCIS
• Intermediate grade DCIS
• Low-grade DCIS

It is thought that low-grade DCIS is less likely to become an invasive cancer than high-grade DCIS.

How is DCIS treated?

The aim of treatment for DCIS is to remove the early cancer cells, to avoid them developing into an invasive cancer, which can spread beyond the milk ducts. 

Surgery for DCIS

1. Surgery to remove the cancer cells is usually the first treatment. You may have part of your breast removed or the whole breast (mastectomy). If you have all or part of your breast removed you may be offered breast reconstruction.
2. Surgery to remove lymph nodes in your armpit area to check if they contain cancer. This is called a sentinel lymph node biopsy. It’s more common if you’re having a mastectomy. Usually there is no cancer in the lymph nodes with a diagnosis of DCIS.

Read more about surgery for breast cancer.

Treatment after surgery

You may have more treatment after surgery to try to reduce the risk of the DCIS coming back or an invasive cancer developing. For example:

• Radiotherapy. Most people will have radiotherapy if part of the breast is removed, unless the area of DCIS was very small and / or low grade. You may or may not have radiotherapy if your whole breast is removed (mastectomy). More about radiotherapy for breast cancer.
• Hormone therapy. If your DCIS has hormone receptors (oestrogen-receptor positive (ER+)), you may have hormone therapy drugs. More about hormone therapy treatment.

After treatment

Having a diagnosis of DCIS means you have a slightly higher risk of getting cancer in the same breast or in your other breast. As a result, you will have yearly screening mammograms after your treatment.