Breast cancer originates in the cells of the breast in both men and women. Globally it is the second most common type of cancer after lung cancer, the fifth most frequent cause of cancer death.
Understanding the basics of breast cancer is an important early step in coming to grips with your new diagnosis. The breast is made up of cells which, under normal conditions, divide and form new cells in an orderly fashion. In cancer, the cells divide in an uncontrolled fashion. By definition, cancer is uncontrolled cell growth. In the early stages, the cells remain in the milk-producing glands (lobules, which make milk) or the ducts (tubes which transport milk from the glands to the nipple). When the cancer cells are confined to the ducts or lobules, the cancer is referred to as in-situ, or non-invasive. These in-situ or non-invasive cancers are considered curable.
With time, some cancers develop the ability to penetrate the lining of the ducts and invade into the surrounding tissue. Tumors that have invaded the lining of the duct are called invasive, or infiltrating, cancers. At first, these invasive tumors are confined to the breast and are at least potentially curable by local removal (lumpectomy and radiation) or by mastectomy.
As the invasive tumors grow, they eventually invade into the surrounding lymphatic or blood vessels of the breast. Once they have invaded these structures, they can spread (metastasize) to other sights in the body. The usual first sight of metastasis is the under arm (axillary) lymph nodes. Cells can also spread to other organs of the body. The most common sites for distant metastasis are the bones, the liver, the brain, or the lung.
Often, there are no symptoms of breast cancer, but signs can include;
- a breast lump or
- an abnormal mammogram
Breast cancer stages range from
- early curable breast cancer to
- metastatic breast cancer