Breast Cancer Surgery

It is important to know whether there are cancer cells in the lymph nodes. This can only be determined by having the glands examined by the pathologist after removing them. The first opportunity to determine this is by ultrasound scan and needle biopsy at the same time as the cancer is detected and biopsied. If the lymph node is negative for cancer cells, then it is necessary to identify the sentinel lymph node (first node in the chain of lymph nodes) and remove it for proper assessment by a technique called Sentinel node biopsy. This is the universally accepted gold standard (of staging the axilla) for determining the need for removing all the lymph nodes (axillary clearance). Additional methods of staging the axilla include axillary sampling.

In 60 – 70% of women with breast cancer the glands or nodes do not contain cancer cells. In these women, it is unnecessary to remove all the lymph glands. If there are cancer cells within the lymph nodes then the addition of chemotherapy in women who still have periods increases the chances of success in treating the cancer by 30%. Also where there are cancer cells in the lymph nodes and all the lymph nodes have not been removed, the remaining nodes will need to be surgically removed or treated with radiotherapy.

Extensive studies have shown that when cancer cells spread from the breast to the lymph nodes they usually follow a predicted path to one or more lymph nodes first before spreading to the other lymph nodes. These one or more lymph nodes (usually one or two) are called sentinel lymph nodes. If these are removed and found to be clear of any cancer cells, then it is assumed ( accurate to 97%) that the remaining lymph nodes are also clear. If the sentinel nodes contain cancer cells, then the remaining lymph nodes need to be removed as there is a chance (40%) that the remaining nodes will have cancer cells in them. Leaving such lymph nodes behind will result in the cancerous lymph nodes getting larger and involving the blood vessels, muscles and nerves in the neighbourhood. This can result in lymphoedema and nerve pain and paralysis of the arm (rare , 1%). This is then extremely difficult to treat. Hence, removing the remaining lymph nodes is necessary.

The accepted gold standard technique for Sentinel Node Biopsy based on its high detection and prediction rates is a combined technique involving injection of radioactive tracer into the skin around the nipple between 3-24hours before the surgery and also a blue dye into the same area at the time of the surgery. The radioactivity is traced with a scanner much like a metal detector which helps find metal in the ground. This is like a compass which tells you the location of the the sentinel node. The blue dye travels along the lymph channels which are coloured blue and act like a SatNav in guiding the surgeon to the precise location of the lymph node.

With the use of a molecular analyzer (OSNA), it can be determined during the surgery whether the sentinel lymph nodes contain malignant cells or not. If they do, the remaining lymph nodes are removed at the same time under the same anaesthetic. Where this facility is available, patients are saved readmission for a second operation on their lymph nodes because the results normally take 1-2 weeks. It also ensures that any risk reducing treatments like chemotherapy can be started approximately 4-6 weeks earlier. The patients also know the result immediately after recovering from the anaesthetic.

When radioactive tracing is not possible, removing four nodes following the injection of blue dye is considered an acceptable alternative.

Axillary node sampling involves removing a few glands to determine if there has been any spread to them (the absolute minimum recommended is 4). The criticism of this technique is that it is random and may result in the involved lymph nodes being missed