Breast Cancer Overview
When cancer forms within the breast tissue, this is known as breast cancer. Cancer is abnormal cell clusters that grow in abnormal patterns. Most of the time, women are the ones who develop this form of cancer, but 1% of all breast cancer cases strike men.
Breast cancer is the second most common form of cancer affecting women today with the first being non-melanoma skin cancers. Breast cancer is the second most common cause for female deaths to cancer after lung cancer.
Back in 2007, the American Cancer Society put out an estimate stating that 178,480 new invasive breast cancer cases would be found in U.S. women along with 62,030 new cases of noninvasive (in-situ) breast cancer. The lifetime invasive breast cancer risk for a woman is around one in eight women or 13%.
The good news is that breast cancer death rates have been declining at a gradual pace and are expected to continue this slow decline. It is believed that the decline is due to greater awareness about the disease and improvements in screening and treatments.
Breasts are made up of fibrous connective tissue, glands, and fat. The breast contains numerous lobes and these are further divided into lobules which are capped by the milk glands. There are small ducts running from a large number of even smaller glands. The ducts connect and are capped by the nipple.
Most breast cancer, 80%, is found in the ducts. This cancer is known as ductal cancer. When cancer develops in the lobules, it is called lobular cancer. Around 10%-15% of all breast cancers are lobular.
Less common forms of breast cancer include: medullary cancer, inflammatory breast cancer, angiosarcoma, phyllodes tumor, mucinous (colloid) carcinoma, Paget's disease, and mixed tumors.
It is quite common for women to have breast changes that are precancerous by nature. These are called in situ changes. In situ is the Latin term for "in site" which means that the changes remain confined to the same spot and haven't spread. If such in situ changes are found in the ducts, this is termed ductal carcinoma in situ (DCIS). This condition can be seen during routine mammography screening.
Sometimes in situ changes occur in the breast lobules. This is termed lobular carcinoma in situ (LCIS).
If breast cancer should spread from its place of origin into surrounding tissue, it is then called infiltrating cancer. If the spreading cancer originated from the ducts, this is called ductal carcinoma. If the spreading cancer originated in the lobules, it is termed infiltrating lobular carcinoma.
Cancer that becomes metastatic is cancer in its most serious form. Metastasis signifies that the cancer has spread far from its original site. When cancer metastasizes, it tends to move into the lymph nodes that are found in the underarm area or just above the collarbone on the same side of the body where the breast tumor originated. Breast cancer can also metastasize to the liver, bones, and brain.