Skip to Content

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.


The week before your procedure:

  • Arrange a ride home. Ask a family member or friend to drive you home after your surgery or procedure. Do not drive yourself home.
  • Ask your caregiver if you need to stop using aspirin or any other prescribed or over-the-counter medicine before your procedure or surgery.
  • Bring your medicine bottles or a list of your medicines when you see your caregiver. Tell your caregiver if you are allergic to any medicine. Tell your caregiver if you use any herbs, food supplements, or over-the-counter medicine.
  • You may need to have a mammogram, chest x-ray, and blood or urine tests. Ask your caregiver for more information about these and other tests that you may need. Write down the date, time, and location of each test.
  • Write down the correct date, time, and location of your procedure.

The night before your procedure:

  • Ask caregivers about directions for eating and drinking.
  • You may be given medicine to help you sleep.

The day of your procedure:

  • You or a close family member will be asked to sign a legal document called a consent form. It gives caregivers permission to do the procedure or surgery. It also explains the problems that may happen, and your choices. Make sure all your questions are answered before you sign this form.
  • Ask your caregiver before taking any medicine on the day of your procedure. These medicines include insulin, diabetic pills, high blood pressure pills, or heart pills. Bring a list of all the medicines you take, or your pill bottles, with you to the hospital.
  • If you wear contact lenses, do not wear them on the day of your procedure or surgery. Glasses may be worn.
  • Caregivers may insert an intravenous tube (IV) into your vein. A vein in the arm is usually chosen. Through the IV tube, you may be given liquids and medicine.
  • An anesthesiologist will talk to you before your surgery. You may need medicine to keep you asleep or numb an area of your body during surgery. Tell caregivers if you or anyone in your family has had a problem with anesthesia in the past.


What will happen:

  • 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 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 over 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. Do not get out of bed until your caregiver says it is okay. 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.


  • You cannot make it to your appointment on time.
  • You have a fever.
  • You have new pain or soreness of your breast.
  • You have clear or bloody discharge from your nipple.
  • You have questions or concerns about your procedure.

Seek Care Immediately if

  • You have chest or back pain, a fast or pounding heartbeat, or trouble breathing.


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.

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 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.