Sentinel Lymph Node Biopsy
Reviewed
Also called: Lymph node biopsy, Sentinel node biopsy, Sentinel lymph node mapping and biopsy
A sentinel lymph node biopsy (SLNB) is a surgical procedure that checks your lymph nodes for cancer cells.
Specimen: Sentinel lymph node tissue
Why this test may be ordered
- To find out whether an early-stage cancer has spread through your lymphatic system to your lymph nodes or other parts of your body
- Most often used for people who have breast cancer or melanoma
- Usually done when the tumor is being removed
- Helps your provider create the best treatment plan for you
Preparation and collection
You will probably need to fast (not eat or drink) for several hours before 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.
A sentinel lymph node biopsy may be done in a hospital or an outpatient surgical center. Your provider will apply medicine to numb the skin over the procedure area. You will be injected with a small amount of a radioactive substance called a tracer near the tumor. You may also be injected with a blue dye that stains the lymph node, making it easier to see. You will be given general anesthesia. The node will be removed and sent to a lab, where it will be checked for cancer cells.
You may have a little bleeding, pain, or bruising at the biopsy site. There is also a small risk of infection, which can be treated with antibiotics. Allergic reactions to the tracer are rare and usually mild. If only the sentinel lymph node is removed, there is a low risk of lymphedema (swelling, usually of the arms or legs) from the lymph fluid. The risk increases with the number of lymph nodes removed. While radiation exposure from the tracer in a sentinel lymph node biopsy is safe for most adults, it can be harmful to a developing baby. So be sure to tell your provider if you are pregnant or think you may be pregnant.
Understanding results
The results will be given as positive or negative. Knowing the stage of your cancer can help your health care provider plan the best treatment for you.
- Positive: If your results are positive, it means cancer was found in the sentinel lymph node and may have spread to nearby lymph nodes and/or other organs. Limitation: 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. Next step: Your provider may recommend removing and testing more lymph nodes to check for cancer cells.
- Negative: If your results are negative, it means no cancer cells were found in the sentinel lymph node, and it's unlikely that the cancer has spread. Limitation: Sometimes, you may have more than one sentinel lymph node. Next step: You will not need to have any more lymph nodes removed. If you have questions about your results, talk to your provider.
- This procedure is only done if you have already been diagnosed with cancer.
- Sometimes, you may have more than one sentinel lymph node.
- Allergic reactions to the tracer are rare and usually mild.
- There is a small risk of infection, which can be treated with antibiotics.
- There is a low risk of lymphedema if only the sentinel lymph node is removed; risk increases with more nodes removed.
What to do next
If you have questions about your results, talk to your provider.
- What does my result mean for my cancer stage?
- Will I need additional lymph node removal or testing?
- What are the signs of infection or lymphedema I should watch for?
- How will this result affect my treatment plan?
- When should I follow up with you after the procedure?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Sentinel Lymph Node Biopsy