Breast cancer is the abnormal growth of the cells that
line the ducts and lobes of the breast. The classification of breast cancer is
Whether the cancer started in the ducts or the
lobules of the breast.
Whether the breast cancer cells have invaded
other tissue in the breast.
What the cancer cells look like under
Classification also takes into consideration such information as how
rapidly the cancer cells are multiplying (tumor grade) and whether breast
cancer cells are present in the nearby lymph nodes.
The following classifications describe the most common types of
In situ: A tumor that
hasn't spread beyond the area where it began is called in situ.
Lobular carcinoma in situ (LCIS): Although not a true cancer, LCIS increases a woman's risk
of developing cancer. For this reason, it's important for women with LCIS to
have a physical exam 2 or 3 times a year, as well as a mammogram every
Ductal carcinoma in situ (DCIS): This is a precancerous condition also called Stage 0
breast cancer. It is noninvasive and is confined to the ducts. Almost all women who have DCIS can be successfully treated. The
best way to detect DCIS is with a mammogram.
Infiltrating (invasive) ductal carcinoma (IDC): This cancer starts in a milk duct, breaks through the
wall of the duct, and invades the fatty tissue of the breast. From there, it
can spread to other parts of the body. IDC is the most common type of breast
cancer, accounting for nearly 80% of cases.
Infiltrating (invasive) lobular carcinoma (ILC): This cancer
starts in the mammary, or milk, glands (lobules) and can spread to other parts
of the body. About 10% of breast cancers are this type.
How this information was developed to help you make better health decisions.