A mastectomy is an umbrella term used for several techniques to remove one or both breasts. In addition, the surgeon may also remove nearby lymph nodes to determine whether the cancer has spread.
During an axillary node dissection, the surgeon removes a number of lymph nodes from your armpit on the side of the tumor.
In a sentinel lymph node biopsy, your surgeon removes only the first few nodes into which a tumor drains (sentinel nodes).
Lymph nodes removed during a mastectomy are then tested for cancer. If no cancer is present, no further lymph nodes need be removed. If cancer is present, the surgeon will discuss options, such as radiation to your armpit. If this is what you decide to do, no further lymph nodes will need to be removed.