Sentinel Lymph Node Biopsy

What Are Lymph Nodes?

Lymph nodes, the size of a pea, are part of the body's lymphatic system-a series of small channels that drain excess fluid from all the tissues of the body back into the bloodstream. As the fluid drains, it passes through the lymph nodes, which act as biologic filters, trapping bacteria, cancer cells or other cellular debris. The lymph nodes then start an immune system response to the trapped particles.

Lymphatic fluid from the breast drains mostly into the lymph nodes located under the arm. The fluid travels through lymph nodes in a step-wise fashion, so nodes 'upstream' are the first to receive the fluid as it leaves the breast and the most likely to contain cancer cells from a breast tumor.

Sentinel Lymph Node Biopsy: A Minimally Invasive Procedure

The sentinel lymph node biopsy came about because surgeons were looking for a less-invasive technique to accomplish the same thing as a full axillary node dissection—but with fewer side effects. In a full axillary lymph node dissection 10-25 lymph nodes are removed which greatly affects the flow of the lymphatic fluid circulation of the arm. During a sentinel lymph node biopsy, an average of one to three sentinel lymph nodes are identified and removed. This is advantageous because the side effects of removing all of the lymph nodes under the arm are greatly reduced or avoided completely. These side effects include excess fluid build up in the arm, called lymphedema, numbness, burning, infection and stiffness.

If the sentinel lymph node(s) do not contain cancer, there is a greater than 95 percent chance that the remaining axillary lymph nodes are also cancer-free.

The procedure begins with an injection of a small amount of radioactive tracer (before you go to the operating room), and with an injection of a blue dye (after you are in the operating room), around the breast cancer.

The radioactive tracer and dye are absorbed by the lymph system. This allows the surgeon to identify the sentinel lymph node(s). These nodes will emit a small amount of radiation and/or will be visibly blue. Once in the operating room, a special device called a gamma probe is used to pick up the radioactive signal.

The surgeon removes these sentinel lymph nodes, identified by the radioactive tracer and/or the blue dyes and sends them to the pathologist. With the patient still in the operating room, the pathologist examines the lymph node(s). The pathologist is able to perform a more intensive analysis of the sentinel lymph node(s), instead of sorting through the 10-25 nodes removed with a full axillary lymph node dissection. If no cancer cells are found in the sentinel lymph node(s), there is no need to remove any additional lymph nodes.

If there are cancer cells present in the sentinel lymph node(s), then a full axillary lymph node dissection will be done. A full axillary lymph node dissection will also be done if the surgeon cannot identify a sentinel lymph node(s) with either the radioactive tracer or the blue dye. Occasionally, a cancer cell in the sentinel lymph nodes is so small that it is impossible for the pathologist to identify during surgery. In these cases, the presence of cancer cells will be reported in the final pathology report. The patient will need to be scheduled for a second surgery to have a full axillary lymph node dissection performed.

Unfortunately, not everyone is a good candidate for sentinel lymph node biopsy. Your surgeon will be able to discuss the benefits, risks and whether or not this procedure is a good choice for you.

Genesis Center for Breast Health team approach using combined resources including primary care physicians, surgeons, radiologists, pathologists, medical oncologists, radiation oncologists, psychologists, nurses, and mammography technologists provides highly specialized, individualized care for the patient undergoing sentinel lymph node biopsy.

For further information, please contact the Center for Breast Health, 563-421-7628.