Surgery can be an excision of the tumour with surrounding normal breast tissue (breast conservation) or removal of the whole breast (mastectomy). Clinical trials comparing mastectomy and breast conservation have shown that the two produce identical results. If the lump is relatively small it is usually possible for the surgeon to remove it along with a small amount of surrounding normal tissue. This is called lumpectomy, wide local excision or breast-conserving surgery. With a larger lump, this breast-conserving operation may not be possible because so much of the breast tissue would have been taken away that it would badly distort the breast. Once the lump and surrounding tissue is removed it needs to be examined under the microscope. In some women, the surrounding tissue is abnormal and a further operation is necessary. A mastectomy (removal of the whole breast) may be necessary if:
the cancer is too large to remove and leave a reasonable looking breast after surgery.
there is more than one lump in the breast.
the cancer is directly underneath the nipple.
the patient has previously had a lumpectomy or wide excision and the tissue round the cancer is abnormal.
As well as removing the lump or breast, the surgeon will also usually remove some or all axillary lymph glands, which are found under the arm. There are about 20 of these lymph glands and they are the most common place for cancer to spread. Knowing whether this has happened and, if so, how many glands are affected is important in both assessing the severity of the cancer and deciding on follow up treatment.If the surgeon needs to check whether the cancer has spread to these glands, then removing either a single gland which drains the cancer or a few of these glands is all that is needed. If however the surgeon wants to find out exactly how many lymph glands are affected, then it is necessary to remove all 20 lymph nodes from the axilla. If it has been decided to treat the patient by mastectomy, the surgeon will probably discuss with her the possibility of having her breast rebuilt at the same time. The results of breast rebuilding or reconstruction are usually more successful if this is performed straight away rather than left until many months or years later. There is no evidence that immediate breast reconstruction makes any recurrence of the cancer more likely. If the cancer does return, reconstruction does not make it harder to detect.