The two main categories of breast cancer are invasive and noninvasive. Non-invasive breast cancers stay within the milk ducts and lobules of the breast. Invasive cancers spread beyond these areas and invade normal tissue. The main noninvasive type is ductal carcinoma in situ DCIS , in which cancer develops in the ducts that carry milk to the nipple but does not spread beyond those ducts. A similar condition, lobular carcinoma in situ, begins in the lobules, the milk-producing glands, and does not grow further. The most common form of breast cancer is invasive ductal carcinoma IDC , sometimes also called infiltrating ductal carcinoma. About 80 percent of all new breast cancer cases in women, and nearly all breast cancer in men, are IDC.
Skip to Content. This is called the stage. Use the menu to see other pages. Staging is a way of describing where the cancer is located, how much the cancer has grown, and if or where it has spread. Doctors use diagnostic tests to find out the cancer's stage, so staging may not be complete until all the tests are finished.
Stage 4 is the most advanced form of breast cancer. It is also referred to as metastatic breast cancer because the malignancy will have spread metastasized from the breast to other parts of the body, such as the bones, lungs, brain, or liver. Stage 4 breast cancer is often diagnosed when the cancer recurs , although it may sometime be discovered at the initial diagnosis.