This may be:

• Full mastectomy - removes all of the breast tissue from the underlying muscles including the nipple-areolar complex. The lymph nodes are left in place. 
• Partial mastectomy - the lump is removed with a surrounding rim of normal breast tissue leaving the rest of the breast intact. This is often followed by radiotherapy. This may not be an option in some cancers.
• Sentinel node biopsy - the first draining lymph node in the axilla is removed and checked for cancer. If there is no cancer seen the rest of the lymph nodes are left intact. If cancer is seen then an axillary node dissection is performed. This technique is not recommended in large or multifocal cancers.
• Axillary node dissection - the lymph nodes in the armpit are removed to remove any cancer there.
• Skin-sparing mastectomy and immediate reconstruction - the breast including the nipple-areolar complex is removed but the skin envelope is preserved. The breast is reconstructed at the time. This option is only suitable for a small number of patients.