Skip to main content

Breast Cancer Sentinel Lymph Node Biopsy

Medically reviewed by Last updated on Aug 31, 2022.

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

A sentinel lymph node (SLN) is usually the lymph node closest to the breast tumor. It is usually found in the armpit, or along the sternum (breastbone) or collarbone. 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 breast cancer has spread outside of your breast. This information can help your healthcare provider decide what other treatments you need.

How do I prepare for a SLNB?

  • You may need a nuclear scan before your procedure. During a nuclear scan, healthcare providers will inject a small amount of radioactive liquid in your breast. 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. He or she may tell you not to eat or drink anything after midnight on the day of your procedure. He or she will tell you what 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.

What will happen during a SLNB?

  • You may be given an antibiotic through your IV to help prevent a bacterial infection. Tell the healthcare provider if you have ever had an allergic reaction to an antibiotic. 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 healthcare provider may use an instrument to help find the SLN. He or she will do this by gently moving an instrument over your skin. The instrument will show pictures of the SLN on a monitor. Your healthcare provider will make a small incision in the skin that covers the SLN. The incision is usually in your armpit or chest. The SLN will be removed and checked for cancer cells. If cancer is found, your healthcare 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 SLNB?

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 closest to the biopsy site may be sore. This should get better within 48 to 72 hours.

What are the risks of a SLNB?

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

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

© Copyright IBM Corporation 2022 Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotes® are the copyrighted property of A.D.A.M., Inc. or IBM Watson Health

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.