Breast cancer starts in the ducts or lobules of the breast. If the cancer cells spread outside the ducts or lobules of the breast into the surrounding tissue, this is called invasive breast cancer. Early breast cancer is an invasive breast cancer. Invasive cancer cells sometimes spread outside the breast area to other parts of the body. They do this by moving through blood vessels, such as veins, or through lymphatic vessels. Lymphatic vessels are next to veins in the body, and are connected to lymph nodes (glands). Lymph nodes collect normal fluid and dead cells from the lymphatic vessels.
If the cancer cells are contained in the breast and armpit area, then the cancer is Žearly breast cancer'. If the cancer has spread to places near the breast, such as the chest (including the skin, muscles or bones of the chest), but the cancer isn't found in other areas of the body, this is called locally advanced breast cancer. If the cancer cells spread from the breast and are found in other areas of the body, such as the bones or the lungs, this is called metastatic breast cancer.
Pre-invasive breast cancer is another type of breast cancer. Pre-invasive breast cancer is the name for abnormal cells or cancer cells that stay inside the milk ducts or milk sacs (lobules) of the breast. Ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) are types of pre-invasive breast cancer.
Paget’s disease of the nipple is a rare form of breast cancer that begins in the milk ducts and spreads to the skin of the nipple and areola (the area around the nipple).
