Management of the sentinel lymph node

In the treatment of breast cancer, the sentinel node is the theorised first lymph node or group of lymph nodes to be affected by the cancer. In this article, a consultant breast and reconstructive surgeon discusses methods for managing sentinel lymph nodes.

What are sentinel lymph nodes?

Lymph nodes are found all over the body, and the ones that are primarily affected by breast cancer are located in the underarm area and around the chest.  When some forms of breast cancer begin to metastasise, they tend to spread along to the lymph nodes first, following the flow of lymphatic fluids. The first lymph node that is affected then becomes the sentinel lymph node – it’s called a sentinel lymph node because a sentinel is someone who keeps watch, and may be the first line of defence. This means that sometimes, they can predict the progression of the cancer, and surgeons can halt it in its tracks.

How are sentinel lymph nodes managed?

A technique that surgeons use to determine if the cancer has infiltrated the lymphatic system is called sentinel lymph node biopsy (SLNB). The procedure involves an injection into the area where the tumour is. This injection could be of a blue medical dye, a radioactive tracer, or a magnetic liquid (Magtrace). The injected substance will disperse into the lymphatic system, following the same route the cancer cells would travel, should they have spread. The injection is typically done just before a larger breast cancer surgical procedure to remove the tumour, where the biopsy is performed concurrently or the biopsy can be performed independently.

Later the same day or the day after, when the surgeons are operating on the patient who will be under a general anaesthetic, they are able to see in which nodes the injected substance has collected – the sentinel node. If the injection is done with a dye, the nodes will be notably discoloured. If the injection is done with a radiotracer, the surgeons will use a monitor to indicate the path and destination of the tracer. If the injection is done with a magnetic liquid, they will use a special magnetic probe to detect exactly where the liquid ended up.

The sentinel nodes are then removed and tested in a laboratory for cancer cells, and results can be generated so quickly that this can happen even as the patient is still in the operating theatre, eliminating the need for multiple procedures. SNLB is explored mostly for patients in the earliest stages of breast cancer.

What happens after a sentinel lymph node biopsy?

If cancer is indeed present and plentiful, then the surgeons may go ahead and remove more lymph nodes around the area as a preventative or diagnostic measure, in what is called an auxiliary lymph node dissection (ALND), although patients who are having breast-conserving surgery or mastectomy with very small amounts of cancer may not require an ALND and the removal of just the sentinel node will be sufficient. Further treatment can also be conducted with radiotherapy to attack cancer cells in the remaining lymph nodes, as an alternative to further surgery.

If you are concerned about breast cancer, you can consult with a specialist on Top Doctors today.