What Is Breast Cancer?
Breast cancer is the growth of abnormal cells in the breast. These abnormal cells grow and divide faster than normal cells. They can also invade the breast and surrounding tissue and spread to other parts of the body. The breast is made up of fat, connective tissue and glandular tissue that forms sections called lobules and lobes (a collection of lobules). The breast (milk) ducts connect the lobes to the nipple. There are a number of different types of breast cancers, most of which begin in the breast ducts.
Breast cancer forms in the breast tissue, most often in the structures called the ducts and lobules. One of the earliest stages of breast cancer is known as ductal carcinoma in situ, or DCIS. In this form of breast cancer abnormal cells are found in the lining of a breast duct. “In situ” means that the abnormal cells have not spread or invaded other breast tissues outside of the duct. Lobular carcinoma in situ, called LCIS, is the name for the abnormal growth of cells in the lobules of the breast. Again, the term “in situ” refers to the fact that the carcinoma, or cancer, has not spread beyond the site of origin.
Breast cancer is a tumor that has become malignant – it has developed from the breast cells. A ‘malignant’ tumor can spread to other parts of the body – it may also invade surrounding tissue. When it spreads around the body, we call it ‘metastasis’. A woman’s breast consists of lobules. Lobules are milk-producing glands. The breast is also full of ducts – milk passages that connect the lobules to the nipple. There is also fatty and connective tissue surrounding the ducts and lobules – this is called stroma. The most common breast cancers start in the cells around the ducts. Others can start in the cells that line the lobules. A smaller number of breast cancers can start in other parts of the breast. The human body has two ways of moving fluid about. One is through the blood stream, which carries plasma, red and white blood cells and platelets. Lymphatic vessels carry tissue fluid, waste products and infection fighting cells (immune system cells). Immune system cells are located in the
