Sentinel Lymph Node Biopsy

Sentinel lymph node biopsy is a procedure in which a single lymph node is identified, removed, and examined for cancer. Lymph nodes are collections of tissue that help filter infections, cancer cells, and other waste substances from the bloodstream. Certain types of cancer can spread to nearby lymph nodes. The cancer spreads to one lymph node first, and then to others. The first lymph node that your cancer could spread to is called the sentinel lymph node. Examining the sentinel lymph node for cancer can help your caregiver plan future treatment for you.


  • Allergies to food or medicine.

  • Medicines taken, including vitamins, herbs, eyedrops, over-the-counter medicines, and creams.

  • Use of steroids (by mouth or creams).

  • Previous problems with numbing medicines.

  • History of bleeding problems or blood clots.

  • Previous surgery.

  • Other health problems, including diabetes and kidney problems.

  • Possibility of pregnancy, if this applies.


  • Infection.

  • Bleeding.

  • Allergic reaction to the dye used for the procedure.

  • Blue staining of the skin where the dye is injected.

  • Damaged lymph vessels, causing a buildup of fluid (lymphedema).

  • Pain or bruising at the biopsy site.


  • Stop smoking at least 2 weeks before the procedure. Not smoking will improve your health after the procedure and decrease the chance of getting a wound infection.

  • You may have blood tests to make sure your blood clots normally.

  • Ask your caregiver about changing or stopping your regular medicines.

  • Do not eat or drink anything for 8 hours before the procedure.


  • You will be given medicine that makes you sleep (general anesthetic).

  • A blue, radioactive dye will be injected near the tumor. The dye will then spread into the sentinel lymph node.

  • A scanner will identify the sentinel lymph node.

  • A small cut (incision) will be made, and the sentinel lymph node will be removed.

  • The sentinel lymph node will be examined in a lab.

Sometimes, a sentinel lymph node biopsy is performed during another surgery, such as a mastectomy or lumpectomy for breast cancer.


  • You will go to a recovery room.

  • You will be monitored for several hours.

  • If complications do not occur, you will be allowed to go home a few hours after the procedure.

  • Your urine may be blue for the next 24 hours. This is normal. It is caused by the dye used during the procedure.

  • Your skin where the dye was injected may be blue for up to 8 weeks.