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Sentinel Lymph Node Breast Biopsy


A sentinel lymph node (SLN) breast biopsy is a procedure to check for and remove lymph nodes that may contain cancer. Sentinel lymph nodes are the first lymph nodes that breast cancer is likely to spread to. Sentinel lymph nodes for the breast are those closest to the tumor. They are usually found in the armpit, or along the sternum or collarbone. Caregivers will remove lymph nodes that appear to contain cancer cells and those close by. The samples are sent to a lab and tested for cancer.


Before your procedure:

  • Informed consent is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.
  • An IV is a small tube placed in your vein that is used to give you medicine or liquids.
  • Anesthesia:
    • Local anesthesia is medicine used to numb an area of your body that will have surgery or a procedure. The medicine may be given in an injection, cream, gel, or patch.
    • General anesthesia will keep you asleep and free from pain during surgery. Anesthesia may be given through your IV. You may instead breathe it in through a mask or a tube placed down your throat. The tube may cause you to have a sore throat when you wake up.

During your procedure:

  • You may be given medicine to help you relax or make you drowsy. You may also be given a local or general anesthesia to make you comfortable during the procedure.
  • Caregivers will then inject a radioactive substance, blue dye, or both near the tumor. A scanner or probe will be used to find the SLN that contains the dye. An incision will be made through your skin overlying the SLN. This SLN will be removed and checked for cancer cells. If cancer is found, one or more lymph nodes are usually removed during the biopsy procedure. The incision will be closed with stitches and covered with bandages to help prevent infection and control bleeding.

After your procedure:

You may be taken to a recovery room until you are fully awake. Caregivers will monitor you closely for any problems. When caregivers see that you are okay, you may be allowed to go home. If caregivers want you to stay in the hospital, you will be taken back to your hospital room. Bandages will cover your stitches to keep the area clean and dry. A caregiver may remove the bandages soon after your procedure to check your wound.

  • Activity: Do not get out of bed until your caregiver says it is okay. Your caregiver may help you get out of bed to walk. If you feel weak or dizzy, sit or lie down right away and tell your caregiver.
  • Medicines:
    • Pain medicine: You may be given a prescription medicine to decrease pain. Do not wait until the pain is severe before you ask for more medicine.
    • Antinausea medicine: This medicine may be given to calm your stomach and to help prevent vomiting.
    • Antibiotics: This medicine is given to help treat or prevent an infection caused by bacteria.
  • Monitoring: Caregivers may check for pulses on your arms or wrists. This helps caregivers learn if you have problems with blood flow after your procedure. You may also have any of the following:
    • Heart monitor: This is also called an ECG or EKG. Sticky pads placed on your skin record your heart's electrical activity.
    • Intake and output: Caregivers will keep track of the amount of liquid you are getting. They also may need to know how much you are urinating. Ask how much liquid you should drink each day. Ask caregivers if they need to measure or collect your urine.


During this procedure, you may have trouble breathing or bleed more than expected. Your lungs, heart, blood vessels, or nerves may be injured, which may lead to more surgery to repair them. You may get an infection. Even with the procedure, the cancer may spread. If you choose not to have a SLN breast biopsy, cancer may spread to other parts of your body.


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 caregivers to decide what care you want to receive. You always have the right to refuse treatment.

Further information

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