Cancer is a group of diseases characterized by cells that change and divide abnormally. If rapid cell division occurs when the body doesn't need new cells, an abundance of tissue is produced. This mass of tissue, known as a tumor, may be either benign or malignant.
Benign tumors are not cancerous and may even be completely harmless. Most of the time these can be surgically removed and do not grow back. The cells of benign tumors don't spread to other parts of the body and do not threaten your life.
Malignant tumors, on the other hand, are cancerous. These tumors can enter and damage surrounding tissues and organs. Cancer cells can also break away from malignant tumors and get in either the blood stream or lymphatic system. When breast cancer spreads outside the breast it usually gets into the lymph nodes under the arms. At this point it probably has already spread to other organs in the body like the liver or lungs, where it will form secondary tumors.
Two forms of cancer affect the breast they are ductal carcinoma and lobular carcinoma. Ductal carcinoma the commonest form of breast cancer, begins in the lining of the breast's ducts. The thin tubes connecting various parts of the breast and which lead to the nipple. Lobular carcinoma is found in the...