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Learn the Facts About Sentinel Lymph Node Biopsy

Cancer that has spread to nearby lymph nodes is often more advanced and may need different therapies. A sentinel lymph node biopsy (SLNB) can help an oncology team accurately determine the stage of the cancer so that they can offer the best possible treatment.  

If your doctor is recommending SLNB for you or a loved one, here are some things to know about the procedure:

Q: What is a sentinel lymph node biopsy and how is it helpful?

A: Lymph nodes are small organs that are part of the body’s lymphatic system. They can play an important role in determining whether cancer cells have spread to other parts of the body because cancer cells often travel through the lymphatic system. During an SLNB, a surgical oncologist will find and remove a patient’s sentinel lymph node—the first node(s) to which cancer cells are likely to spread from the main tumor site.

“Sentinel lymph node biopsy is one of the best strategies we currently have to identify early spread of cancer,” explained Jeffrey Farma, MD, FACS, a surgical oncologist at Fox Chase Cancer Center. “It allows us to more accurately stage a patient’s cancer and determine whether they may have a higher-risk tumor.”  

Q: Who might benefit from SLNB?

A: SLNB is usually performed on patients with breast cancer, melanoma, or merkel cell carcinoma. For melanoma patients, SLNB is only done when the cancer has a high risk of spreading but there aren’t other signs of enlarged lymph nodes.  

Q: How is SLNB performed?

A: SLNB is a minimally invasive procedure that is usually done at the same time that a primary tumor is removed, Farma explained. The surgery has three parts:

  • First, the sentinel node is located by injecting a radioactive or blue dye (or both) near a tumor.
  • Next, the node is taken out through a small incision.
  • Finally, the node is examined by a pathologist to see whether it’s cancerous. This includes special stains and slices of the lymph node and can take 7–10 days.  

Q: Are there any risks to having SLNB?

A: Like all procedures, SLNB has the potential for a few negative side effects. The main one is lymphedema—uncomfortable swelling caused by the backup of lymph fluid. Allergic reactions to the dye used to find the sentinel node can happen as well, but they’re rare.

Q: What do the results of SLNB mean?

A: If the SLNB is positive, the node is cancerous and a patient’s cancer is assigned a more-advanced stage. A positive SLNB might mean that cancer has spread to other lymph nodes, which may also need to be removed. The cancer might have spread to other organs as well.

If the SLNB is negative, the node is not cancerous and a patient’s cancer is assigned a less-advanced stage. A negative SLNB also usually means that cancer hasn’t spread to other nodes or organs, and other lymph nodes won’t need to be removed.

SLNB can give your care team a more accurate picture of your cancer and help them recommend treatment options.