Most Common Types of Breast Cancer

Carcinoma in situ (in SIGH-to): This term is used to describe the early stage of cancer, when it is confined to the place where it originated, typically the ducts or the lobules. It has not yet spread into the fatty tissues in the breast or to other organs in the body.

Ductal carcinoma in situ (DCIS): This is the most common type of noninvasive breast cancer and almost all women at this stage can be cured with treatment. DCIS means that the cancer is confined to the ducts and has not spread through the walls into the fatty tissue of the breast. A mammogram is the best way to detect DCIS in its early stage.

Lobular carcinoma in situ (LCIS): This is not a true type of cancer; however, having LCIS increases a woman's risk of getting cancer later. It originates in the milk-producing glands but does not go through the wall of the lobules. It is very important that women with LCIS frequently check for signs of breast cancer and follow screening guidelines.

Infiltrating (invasive) ductal carcinoma (IDC): This is the most common type of breast cancer. It originates in a milk passage or duct, spreads 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 accounts for about 80% of invasive breast cancers.

Infiltrating (invasive) lobular carcinoma (ILC): This type of cancer originates in the milk glands or lobules. It can then spread to other parts of the body. ILC accounts for about 10% of invasive breast cancers.   

There are also several other less common types of breast cancer that are not mentioned on the list above. To find out more information on other type of breast cancer, please visit the American Cancer Society website at www.cancer.org.