Types of Breast Cancer

The most common type of breast cancer begins in the lining of the ducts and is called ductal carcinoma. Another type, called lobular carcinoma, arises in the lobules.

When breast cancer spreads outside the breast, cancer cells are often found in the lymph nodes under the arm (axillary lymph nodes). If the cancer has reached these nodes, it may mean that cancer cells have spread to other parts of the body--other lymph nodes and other organs, such as the bones, liver, or lungs--via the lymphatic system or the bloodstream.

Cancer that spreads is the same disease and has the same name as the original (primary) cancer. When breast cancer spreads, it is called metastatic breast cancer, even though the secondary tumor is in another organ. Doctors sometimes call this "distant" disease.