A lumpectomy is the removal of a benign or malignant tissue mass, most commonly performed on the breast. It is considered ‘breast-conserving’ surgery because in a lumpectomy only the tumour, and a surrounding margin of normal breast tissue, is removed. In the case of a malignant breast tumour, and depending on its location and size, some or all of the lymph nodes in the corresponding armpit (axilla) may also be removed to detect for invasion of cancer cells. This procedure is called lymph node dissection.

The location, size, and type of tumour are of primary importance when considering breast cancer surgery options. The extent and severity of a cancer is evaluated or ‘staged’ according to a fairly complex system. Considerations include the size of the tumour and whether the cancer has spread to other areas. In the unfortunate event the cancer has spread, other treatments are considered and offered. Women with early stage breast cancers are usually the best candidates for lumpectomy, however in most cases a course of radiation therapy after surgery is advised as part of the treatment plan.