The name ductal cancer in situ, refers to a specific diagnosis of cancer. This is a very early type of cancer which is curable in more than 97% of all women. Ductal cancer in situ is isolated within the breast duct, and has not spread to other parts of your breast. Treatment is local, occurring only at your breast. Treatment often consists of removing the lump from the breast, and is often followed by radiation therapy to the affected area.

Breast cancer confined to the duct spreads to the lymph nodes under the arm only 1% of the time. It is rarely treated with chemotherapy.

The ducts carry milk to the nipple from the milk glands, or "lobes."