Sentinel Lymph Node Biopsy

A sentinel lymph node biopsy (SLNB) is a surgical procedure that checks your lymph nodes for cancer cells. An SLNB is only done if you have already been diagnosed with cancer. This procedure finds, removes, and checks the sentinel lymph node to determine the stage of your cancer.

Cancer staging is usually based on the size of your tumor and whether the cancer has spread (metastasized) to nearby areas, lymph nodes, or other parts of your body. Knowing the stage of your cancer can help your health care provider plan the best treatment for you.Your lymph nodes are located throughout your body, including your underarms, neck, chest, abdomen (belly), and groin. They are part of the lymphatic system, which helps to protect you from illness and maintain healthy fluid levels in your body.

Your lymphatic system is part of your body’s immune system. Your lymph fluid carries fluid and cells throughout your body to help fight infections. It may also filter cancer cells (if there are any).

But sometimes, with certain cancers such as breast cancer and melanoma (the most serious type of skin cancer), some cancer cells may spread to your lymph nodes. Cancers spread when cells break off from the original (primary) tumor and are carried by the lymphatic system to other parts of your body. The sentinel lymph node is the first lymph node where these types of cancers are most likely to spread.

It’s usually located near the original tumor site and may receive drainage from the tumor. Your provider tests your sentinel lymph node to see if your cancer has spread. Sometimes, you may have more than one sentinel lymph node.

Why this test is done

You may need this test if you've been diagnosed with breast cancer, melanoma, or certain other types of cancer. It can show whether your cancer is spreading and help your provider create the best treatment plan for you.

How to prepare

You will probably need to fast (not eat or drink) for several hours before the test. You may also need to stop taking blood thinners, such as aspirin, for a certain time before your test. Your provider will let you know when you need to stop taking your medicine and anything else to do to prepare for the test.

In addition, be sure to arrange for someone to take you home. You may be groggy and confused after you wake up from the procedure.

Sample type

Tissue/Biopsy

Other names for this test

lymph node biopsy, sentinel node biopsy, sentinel lymph node mapping and biopsy