Unfortunately, not always. In many cases, those who undergo a breast lump excision or lumpectomy may require a second surgery.After a breast lump excision, the tissue excised from the breast is examined by a pathologist to see if cancer cells are present in the margins surrounding the cancerous tumor. If there are cancer cells in the margins, the surgeon may recommend one more surgery, called re-excision lumpectomy to clear the margins. If cancer cells are still present after re-excision, the surgeon may need to perform a mastectomy or removal of the entire breast.