The first sign of breast cancer is usually a lump or a spot seen on a mammogram. Like all cancers, the disease is the result of unrestrained multiplication of cells. Normal cells divide in a planned way, creating more cells only when needed. Cancerous cells grow and divide without control or order, often making excess tissue that becomes a tumor. Cancer cells may grow into nearby healthy tissue, or they may break away from the tumor and travel through the blood stream or lymphatic system to other parts of the body. For this reason, breast cancer often spreads into the lymph nodes in the armpit, chest, and collarbone area. To find out what stage the cancer is in, your doctor will measure the lump, check to see if the cancer has spread, and perform tests such as another mammogram, a biopsy, and body scans. The results of the tests will help you and your doctor decide on a treatment plan. Left untreated, cancer eventually will spread. Almost all forms of cancer therapy have unpleasant side effects, and may fail to halt the spread. However, treatment---especially when performed early enough---usually improves your chances .
