Sentinel Node Study

Expertise in Sentinel Lymph Nodes Biopsy

A biopsy of the sentinel lymph nodes provides a roadmap that shows doctors the direction of lymphatic drainage from around the site of cancer. Oncologists (cancer doctors) use this procedure for people with breast cancer, melanoma and other types of cancer.

Before sentinel node biopsy existed, the surgeon would make their best estimate about the direction of lymph drainage from a tumor to the lymph nodes. The surgeon would remove many lymph nodes in the area that they estimated to be within the drainage pathway. A specialist would then microscopically examine those lymph nodes for signs of the spread of the cancer. Another name for this procedure is lymphoscintigraphy.

Benefits of Sentinel Node Biopsy

Thanks to the sentinel node study, the surgeon can much more precisely target the actual path of lymphatic drainage. This allows the surgeon to take out the specific node (or nodes) that are the first to receive lymphatic drainage from the area around the tumor.

If the node(s) don’t show any microscopic evidence of tumor, it is very unlikely that any other nodes would contain any tumor cells. Since the surgeon now needs to remove fewer nodes, your surgery is less extensive and your recovery is faster.

The procedure typically involves no special preparation. Your surgery team provides you with any needed instructions.

What To Expect

Sentinel node biopsy is a type of nuclear medicine. With this procedure, the doctor injects a small amount of radioactive material in the region of the tumor. There are usually four to eight injections, depending on the type of tumor. The injections can feel like bee stings, but the pain usually subsides after a few seconds.

The exam may or may not involve imaging. In cases where the surgeon requests imaging, the technologist and the doctor work together to image lymph nodes in the region around the tumor. If they see lymph node drainage, the doctor may use a pen to put a mark on the skin overlying the lymph node to help the surgeon find the nodes.

In the operating room, the surgeon has a probe that detects the radioactivity in the lymph nodes. The surgeon uses the probe alone or with the pictures to identify the sentinel node(s). Once the surgeon removes the nodes, they send them to pathology for microscopic examination for evidence of the spread of the tumor.

Your Safety

As with most nuclear medicine studies, the radiation dose from this test is very small and therefore safe. In addition, the surgeon will likely remove much of the skin and the lymph nodes that contain the greatest amount of the injected radioactivity. The rest of the radioactivity will decay quickly. Following surgery, you won’t need to take any special precautions.