What is ductal carcinoma in situ (DCIS)?

What is ductal carcinoma in situ (DCIS)?

Ductal carcinoma in situ (DCIS) is a type of breast cancer. This is also called non-invasive or pre-invasive breast cancer. The cancer cells are found along the sides of the milk duct within the breast. Milk ducts are within each breast and are the tubes that let milk travel from the lobes (made up of lobules) to the nipple openings for breastfeeding.

DCIS is non-invasive, which means that the cancer cells are found only within the milk duct(s) and have not spread through the walls of the ducts and to other nearby tissues in the breast. It is a Stage 0 breast cancer and is treatable. Doctors characterize cancer in stages, using Roman numerals from 0, or zero, to IV, or four. In order to determine the stage of a tumor, doctors must look at the original tumor and determine where it is located, its size, and if it has been noticed in other areas. The lower the stage number, the better chance for successful treatment of the disease and for the best results.

Although DCIS is always considered Stage 0, the tumor can be any size and may be found within several milk ducts inside the breast. With proper treatment, the prognosis is excellent.