Lumpectomy (aka: tylectomy) is a common surgical procedure designed to remove a discrete lump, usually a benign tumor or breast cancer, from an affected man or woman's breast. As the tissue removed is generally quite limited and the procedure relatively non-invasive, compared to a mastectomy, a lumpectomy is considered a viable means of "breast conservation" or "breast preservation" surgery with all the attendant physical and emotional advantages of such an approach.
Mastectomy is the medical term for the surgical removal of one or both breasts, partially or completely. Mastectomy is usually done to treat breast cancer; in some cases, women and some men believed to be at high risk of breast cancer have the operation prophylactically, that is, to prevent cancer rather than treat it. It is also the medical procedure carried out to remove breast cancer tissue in males.