A lumpectomy is a breast-conserving surgery that removes abnormal or cancerous tissue from the breast. Unlike a mastectomy, which removes the entire breast, a lumpectomy is designed to only remove a smaller portion of the breast. Normal tissue is also extracted around the lump to ensure that all the cancerous tissue is removed. A lumpectomy is usually performed to verify a diagnosis of cancer or to treat the early stages of cancer. Most commonly, if a woman chooses a lumpectomy, radiation therapy will be required to decrease the chances of the cancer returning.