With ductal carcinoma in situ (DCIS), cancer cells are found only in the lining of the breast duct and have not spread outside the duct into nearby breast tissue or to other organs in the body.
DCIS is the most common type of non-invasive breast cancer. It may also be called intraductal carcinoma or non-invasive ductal carcinoma. Nearly all women diagnosed with this early stage of breast cancer can be successfully treated.
Women with DCIS have an increased risk of developing an invasive ductal carcinoma. However, it is not yet known how to identify which DCIS will progress to an invasive cancer, and which will not.
DCIS may be classified based on what the cells look like when viewed under the microscope. There are 2 main subtypes of DCIS: comedo and non-comedo.
The term comedo is used to describe the appearance of DCIS cells. When examined under a microscope, the cells have dead material (necrosis) that plugs the middle. This material can be squeezed or expressed out of the cells, like a blackhead (comedo) on the skin.
Comedo DCIS tends to grow quickly and spread into surrounding breast tissue.
Non-comedo DCIS grows more slowly than the comedo type of DCIS, and is less likely spread into the surrounding breast tissue.
There 3 are different types of non-comedo DCIS:
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