Types of breast cancers

Types of breast cancers

There are several types of breast cancer, but some of them are quite rare. In some cases a
single breast tumor can be a combination of these types or be a mixture of invasive and in
situ cancer.
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is the most
common type of non-invasive breast cancer. DCIS means that the cancer cells are inside
the ducts but have not spread through the walls of the ducts into the surrounding breast
tissue.
About 1 in 5 new breast cancer cases will be DCIS. Nearly all women diagnosed at this
early stage of breast cancer can be cured. A mammogram is often the best way to find
DCIS early.
When DCIS is diagnosed, the pathologist (a doctor specializing in diagnosing disease
from tissue samples) will look for areas of dead or dying cancer cells, called tumor
necrosis, within the tissue sample. If necrosis is present, the tumor is likely to be more
aggressive. The term comedocarcinoma is often used to describe DCIS with large areas
of necrosis. The pathologist will also note how abnormal the cells appear, especially the
part of cells where DNA is found (the nucleus).
Lobular carcinoma in situ
This is not a true cancer or pre-cancer, and is discussed in the section “What are the risk
factors for breast cancer?”