Usually some of the lymph nodes under the arm are taken out. In most cases, radiation therapy follows. Sometimes lymph nodes under the arm are also taken out. This is the most common operation for breast cancer. For many years, this was the operation most used, but it is used now only when the tumor has spread to the chest muscles.
Chemotherapy is the use of drugs to kill cancer cells.
Chemotherapy may be taken by mouth or it may be put into the body by inserting a needle into a vein or muscle. Chemotherapy is called a systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells outside the breast area. If tests show that the breast cancer cells have estrogen receptors and progesterone receptors, hormone therapy may be given. Hormone therapy is used to change the way hormones in the body help cancers grow. This may be done by using drugs that change the way hormones work or by surgery to take out organs that make hormones, such as the ovaries.