Sentinel Lymph Node Biopsy

Medically reviewed by Drugs.com. Last updated on Apr 6, 2025.

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What do I need to know about a sentinel lymph node (SLN) biopsy?

A SLN is usually the lymph node closest to a tumor. A biopsy is a procedure used to find and remove a SLN. During the biopsy, the SLN will be tested for cancer cells. If the test is positive, it may mean that cancer has spread to other places in your body. This information can help your healthcare provider decide on treatment you may need.

How do I prepare for a sentinel lymph node biopsy?

• You may need a nuclear scan before your procedure. During a nuclear scan, healthcare providers will inject a small amount of radioactive liquid near the tumor. Radioactive liquid will move to the location of your lymph nodes and help them show up better in pictures. A camera will take pictures of the lymph nodes. The pictures will help your healthcare provider plan for your procedure.
• Your healthcare provider will talk to you about how to prepare for your procedure. You may be told not to eat or drink anything after midnight on the day of your procedure. Your provider will tell you which medicines to take or not take on the day of your procedure. You may be given contrast liquid during your biopsy. Tell your healthcare provider if you have ever had an allergic reaction to contrast liquid. Arrange for someone to drive you home and stay with you after your procedure.

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What will happen during a sentinel lymph node biopsy?

• You may be given an antibiotic through your IV to help prevent a bacterial infection. You may be given general anesthesia to keep you asleep and free from pain during your procedure. You may instead be given local anesthesia to numb the area. With local anesthesia, you may still feel pressure or pushing during the procedure, but you should not feel any pain.
• Your healthcare provider will inject blue contrast liquid, radioactive liquid, or both near the tumor. The liquid will move to the SLN. Your provider may use an instrument to help find the SLN. Your provider will do this by gently moving an instrument over your skin. The instrument will show pictures of the SLN on a monitor. Your provider will make a small incision in the skin that covers the SLN. The SLN will be removed and checked for cancer cells. If cancer is found, your provider may remove several more lymph nodes for testing. Your incision may be closed with stitches or strips of medical tape and covered with a bandage.

What will happen after a sentinel lymph node biopsy?

Healthcare providers will monitor you until you are awake. You may be able to go home after you are awake and your pain is controlled. Your urine or bowel movement may be blue for 24 to 48 hours after your procedure. This is caused by the blue contrast liquid given to you during the procedure. You may have bruising or swelling at the biopsy site. This is normal and expected. The arm or leg closest to the biopsy site may be sore. This should get better within 48 to 72 hours.

What are the risks of a sentinel lymph node biopsy?

You may bleed more than expected or get an infection. You may develop a condition called lymphedema. Lymphedema is tissue swelling in the body part nearest to where the SLN was removed. You may have long-term pain or discomfort in this area. Your skin in this area may be permanently thick or hard. Your nerves may be damaged during your procedure. This may cause numbness or tingling where the SLN was removed. It may also cause trouble moving the body part closest to the SLN. You may have an allergic reaction to the contrast liquid. This may require medicine or other treatments.

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