Treatments for ductal carcinoma in situ

The following are treatment options for ductal carcinoma in situ (DCIS), which is stage 0 (non-invasive, or in situ) breast cancer. Your healthcare team will suggest treatments based on your needs and work with you to develop a treatment plan.

DCIS is the most common type of non-invasive breast cancer. It can't spread outside the breast but, if left untreated, it may turn into an invasive breast cancer that can then spread to lymph nodes and other parts of the body.

The goal of treatment for DCIS is to prevent the cancer from becoming invasive breast cancer.

Surgery is the main treatment for DCIS. You may be able to choose the type of breast surgery you have.

Breast-conserving surgery (BCS) is the most common type of surgery for DCIS. Lymph nodes are not usually removed after BCS because DCIS has not spread outside of the duct in the breast.

A mastectomy with or without reconstruction may be offered to treat DCIS if:

• there are many areas of DCIS in the breast
• the cancer can't be completely removed by BCS
• the tumour is very large and removing it might make your breast look unnatural, even after reconstruction
• cancer cells are found in the tissue surrounding the tumour after BCS (called a positive surgical margin)
• there is a high risk of the cancer coming back (recurring) without radiation therapy and you want to avoid having radiation therapy

You will have a sentinel lymph node biopsy during a mastectomy in case invasive cancer is found in the breast tissue that was removed.

Find out more about surgery for breast cancer.

Radiation therapy uses high-energy rays or particles to destroy cancer cells.

External radiation therapy is usually given after BCS for DCIS. It is used to lower the risk that cancer will come back in the breast, especially if you are young or if there is high-grade DCIS.

In rare cases, radiation therapy isn’t needed after BCS because the DCIS is low grade, it is only in one very small area of the breast and it is completely removed with surgery.

Radiation therapy is usually not needed after a mastectomy for DCIS.

Find out more about radiation therapy for breast cancer.

Hormone therapy may be offered after BCS for hormone receptor–positive DCIS. It can lower the risk of DCIS recurring, or of invasive cancer in that breast and the other breast.

Hormone therapy may be offered after a mastectomy to lower the risk of cancer in the other breast.

The most common type of hormone therapy used is tamoxifen.

Find out more about hormone therapy for breast cancer.

Talk to your doctor about clinical trials open to people with breast cancer in Canada. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.