The removal of some or all of the lymph nodes in your armpit (axilla) is an integral part of breast surgery. Whether or not lymph node(s) are involved with cancer is an important part of staging breast cancer.

For women in whom the lymph nodes in the armpit are normal feeling on physical examination or imaging (eg on ultrasound or mammogram or MRI scans) modern breast surgery starts with a sentinel lymph node biopsy (SLNBx). To do this, you will need to have a small injection of low dose radioactive material into your breast either on the afternoon before your surgery or the morning of your surgery (depending on where you are having your operation). You may be asked to massage your breast following the injection and you will then be scanned intermittently till the radioactive tracer has been detected in one or more lymph nodes in your armpit or between the ribs. This will act as a guide for your surgeon to remove these few glands (nodes). Your surgeon may in addition inject a blue dye into your breast during your surgery and this will come out in your urine and turn it a green / blue colour temporarily. The SLN, along with any breast specimens will be sent for examination under a microscope. For the majority of women presenting with early stage breast cancer the sentinel nodes will be negative, that is there will be no evidence of cancer in them, however approximately 25-30% of women will have evidence of cancer having already spread into their sentinel node. This will be discussed in the MDT and the pros and cons of whether to go back and remove the remaining lymph glands (axillary clearance) will be discussed. More recent research has shown that for many patients who complete their radiotherapy + any other recommended treatments, observing the remaining lymph nodes is safe and does not negatively impact on either the risk of the cancer coming back in the armpit or the risk of the cancer returning elsewhere in your body. There are however still some specific circumstances where your surgeon will recommend that you have an axillary clearance to remove the remaining lymph nodes in your armpit. Typically this is when there is a risk that other treatments such as chemotherapy and radiotherapy will not be sufficient on their own. Most commonly for women who present with clinical evidence of cancer already in their lymph nodes your surgeon will recommend an up front axillary clearance. The reason for only performing an axillary clearance when this is necessary is that there are some potential risks associated with complete lymph node removal. The most common is numbness in the armpit region that extends down over the back of the upper arm. Another potential side effect is development of lymphoedema, which is swelling of the arm. Most women do not develop lymphoedema but up to 20% may experience mild swelling whereas severe lymphoedema only occurs in about 5% of patients who have had an axillary clearance.