Breast-conserving surgery (lumpectomy) is the surgical removal of a breast lump and some of the tissue around it. The lump (and sometimes some of the lymph nodes under the arm) is removed and sent to the lab for examination.
Breast-conserving surgery can be used in early-stage breast cancer and when the breast lump is small compared with the size of the breast. In most cases, radiation therapy is used after breast-conserving surgery.
WebMD Medical Reference from Healthwise