As the name implies, breast-conserving surgeries remove the tumor, but strive to leave as much of the breast otherwise intact as possible. There are two types of breast-conserving surgeries:
Lumpectomy (sometimes called excisional biopsy or wide excision), which is the removal of the lump in the breast and some of the tissue around it. Most cancer surgeons also remove some of the lymph nodes under the arm.
Partial or segmental mastectomy, which is the removal of the tumor, as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor. Usually, some of the lymph nodes under the arm are removed.