Lumpectomy (sometimes known as a tylectomy) is a surgical removal of a discrete portion or "lump" of breast, usually in the treatment of malignant tumor or breast cancer. It is considered a viable breast conservation therapy, as the amount of tissue removed is limited compared to a full-breast mastectomy, and thus may have physical and emotional advantages over more disfiguring treatment. According to the National Comprehensive Cancer Network guidelines, lumpectomy may be performed for ductal carcinoma in situ (DCIS), for invasive ductal carcinoma, or for other conditions.