Breast cancer lumpectomy is a surgical procedure for the treatment of breast cancer. It is also called breast-conserving surgery as you can retain your breast while removing the cancer tumors. Unlike a mastectomy, only a portion of the breast is removed. A blue dye is injected prior to the surgery in the breast tissues that travels down to the lymphatic channels to the lymph node. The portion for lymph node is marked and isolated to be then surgically removed.