Why would a doctor perform a lumpectomy?

Remove mass: The term lumpectomy has many uses. We typically use it when we refer to taking out a cancerous lump (remove mass, leaving rest of breast intact). Some use it as a general term to mean taking out a noncancerous lump. Both require surgery with anesthesia. Prior to having any surgery, a core needle biopsy should be performed to determine if the lump is cancerous or not.

Breast conservation: A lumpectomy is performed to remove breast cancer with a margin of normal tissue around it. This is performed in order to conserve the breast. We know that having a lumpectomy with radiation versus a mastectomy has the same survival outcome.