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Axillary lymph node surgery
The lymph of the breast is drained by the lymphatic channels to the nodes in the armpit of the same side. These nodes form what is called the axillary lymph node chain. To find out the potential spread of cancer for each breast, axillary lymph nodes are examined for cancer cells. The only way of analysing these nodes is to remove them. A simple palpation or x-ray is not sufficient to determine if the nodes have been reached by the cancer or not.
The removed nodes are sent to the pathologist for analysis. The data from the analysis are available a few days after the operation. This examination is important for determining the choice of postoperative treatments (radiotherapy, Chemotherapy, etc.)
The invasion of the axillary lymph nodes is a significant element in planning breast cancer treatment.
The lymphatic channels drain the lymph fluid (and therefore the tumour cells that are potentially circulating in it) primarily to the first nodes of the chain, known as the sentinel nodes (there are usually 2 or 3). These nodes – also called level 1 nodes – are located along the axillary edge of the breast, where the mammary gland joins the armpit. Level 2 corresponds to the axillary lymph nodes higher up, underneath the pectoralis minor muscle. Level 3 are the nodes located at the top of the arm pit, above the pectoralis minor muscle and under the collarbone. The lymph nodes in the armpit form a 'chain': if the level 1 nodes are free of cancer, then the level 2 and 3 nodes will not be affected.
Si les Ganglions sentinelles ne contiennent pas de cellules tumorales, les autres ganglions de l’aisselle sont à priori indemnes.
The surgeon removes a sample of the sentinel nodes to analyse them: if no tumour cells are found, he does not touch the other nodes. This technique can significantly reduce the number of nodes removed compared with Axillary dissection and thus reduce the risk of postoperative sequelae. It requires experienced surgeons.
Identification, biopsy and analysis of sentinel nodes
To identify the sentinel nodes
The product is a blue dye and/or isotopic marker, i.e. a product which emits rays that are invisible to the eye (equivalent to X-rays). In the case of the latter, the marker is usually injected the day before the procedure, and a scintigraphic examination (a sort of x-ray) is performed to locate the sentinel lymph nodes.
The sentinel lymph nodes are removed and examined, most often in the operating room, by the pathologist looking for tumour cells: this is known as a ‘frozen section examination’ (which takes place during the surgical procedure). If the sentinel lymph nodes are healthy, then it is not necessary to collect more nodes. However, if one or several sentinel nodes are affected, it is essential to carry out an axillary dissection (other nodes in the armpit are removed). If the sentinel lymph nodes are affected, the other nodes in the armpit are invaded in 40% of cases, which will mean that different treatments are proposed.
Unfortunately, the frozen section examination is not completely reliable and the definitive answer can only be given by the pathologist a few days later. If the frozen section examination is negative but the final answer is positive, then it is necessary to complete the dissection... Around 5% of patients who undergo the sentinel lymph node technique must be re-operated on a few days later, to complete the dissection.
Frozen section examination of sentinel lymph nodes
The sentinel lymph node technique cannot be offered to everyone
This technique is not considered :
- if it is suspected either by clinical examination or by puncture test that the lymph nodes are invaded ;
- when Chemotherapy or irradiation was performed before surgery (no study has demonstrated for the moment that the sentinel lymph node biopsy is reliable in these conditions) ;
- when the patient has already had a surgical biopsy of a tumour near the armpit. This biopsy would have created a cavity in the breast, which as a result would have cut off the lymphatic channels leading from the tumour to the lymph nodes.
- in the case of a large tumour (more than 5 cm) or multifocal cancer in several quadrants of the breast (multicentric cancer): in these cases, it is better to perform an axillary dissection.
Axillary lymph node dissection
- A traditional axillary dissection removes only the level 1 nodes and lymph nodes from the lower part of level 2. Generally, around ten nodes are removed (compared with around 20 in the case of a full axillary dissection).
- A full axillary dissection removes the lymph nodes on all levels of the axillary chain (1, 2 and 3). This type of dissection is now very rarely carried out.
In the case of breast-Conserving treatment, the incision for the Axillary dissection measures between 5 and 7 cm and is located in the armpit.
For mastectomies with axillary dissection, the surgeon accesses the armpit using the same incision as for the mastectomy
Innovation: Identifying lymph node involvement before surgery
It is possible to get an idea of a patient’s lymph node involvement before surgery. In a woman with possible lymph node involvement, an ultrasound of the armpit coupled with fine needle aspiration (ultrasound-guided puncture) can sometimes show a lymph node involvement. The surgeon will then proceed immediately to an axillary dissection and not to a biopsy of the sentinel lymph nodes.
In the event of lymph node involvement, certain scanners focusing on the lymph nodes can distinguish a partial involvement of the armpit, enabling a partial dissection; whereas without this information a more extensive dissection would have been carried out (ref...).
During an axillary dissection, using very high quality imaging, the surgeon can carry out less aggressive dissection actions, while preserving the nodes that drain the arm (ref).