What Is a Sentinel Lymph Node Biopsy?

A sentinel lymph node biopsy is a technique for examining axillary (armpit) lymph nodes. This technique is used to identify cancer cells in the lymph nodes. The sentinel node is the first lymph node into which a breast tumor drains and is the one most likely to contain cancer cells. By removing just the “sentinel” nodes (can be one to four sentinel nodes) doctors will be able to tell with a great degree of accuracy, and much less surgery, if cancer has spread into the lymph nodes.

Depending on the results, this may mean avoiding more extensive surgery. Virtua surgeons have been specially trained in identifying sentinel nodes and performing sentinel node biopsies. Your surgeon will discuss this option with you.

How is the biopsy performed?

Surgeons use a radioactive tracer and blue dye to locate the sentinel lymph nodes. In the nuclear medicine department, a small amount of a radioactive tracer material is injected into your breast around the tumor site. Some women state that they experience some temporary burning or stinging when the material is being injected.  The tracer contains less radiation than an x-ray or bone scan. In the operating room, a blue dye is injected into the breast tissue to help visually identify the location of the sentinel lymph node. The lymphatic vessels carry the radioactive material and dye from the tumor site to the sentinel node just as a cancer cell might travel.

After allowing time for the radioactive material and dye to travel, the surgeon examines the tissue for the blue discoloration and uses a small probe to identify the radioactive material. After the sentinel lymph node(s) are located, the surgeon will make a 1- to 2-inch incision and remove the sentinel node(s) for the pathologist to examine. A sentinel lymph node biopsy does not usually require the placement of a surgical drain.

The sentinel nodes will be examined by a pathologist. The results often are reviewed with you at the time of your post-operative office visit. The main significance of finding lymph nodes with cancer cells is on your treatment plan. If cancer cells are found in the sentinel nodes, chemotherapy may be added to your treatment plan. In the past, it could also mean additional lymph node removal, but this may not be necessary. This should be reviewed with your surgeon.

In this case, your surgeon will discuss with you the possibility of removing additional lymph nodes or other treatment options.

Updated January 14, 2022