Sentinel Lymph Node Biopsy

Medically reviewed by Drugs.com. Last updated on Jun 30, 2025.

• Care notes
• Ambulatory
• Discharge
• Español

AMBULATORY CARE:

What you need to know about a sentinel lymph node biopsy (SLNB):

A SLNB is used to see if cancer has spread in your body. Cancer spreads first to sentinel lymph nodes. A biopsy is a procedure to remove the lymph nodes so they can be tested for cancer. Your healthcare provider will use the results of your SLNB to plan tests or treatment, if needed.

How to 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 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. Arrange for someone to drive you home and stay with you after your procedure.
• Tell your provider about all your current medicines. Your provider will tell you if you need to stop any medicine for the procedure, and when to stop. 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.

What will happen during a SLNB:

• 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 move an instrument over your skin that 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 to expect 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 or leg closest to the biopsy site may be sore. This should get better within 48 to 72 hours.

Risks of a SLNB:

You may bleed more than expected or get an infection. You may develop lymphedema (swelling from lymph fluid buildup) in the arm 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 the procedure. This may cause numbness or tingling where the SLN was removed. It may also cause difficulty 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.

Seek care immediately if:

• Blood soaks through your bandage.
• Your stitches come apart.
• Your bruise suddenly gets larger and feels firm.

Related medications

Call your doctor or oncologist if:

• You have a fever or chills.
• Your wound is red, swollen, or draining pus.
• You have nausea or are vomiting.
• Your skin is itchy, swollen, or you have a rash.
• Your pain does not get better after you take medicine for pain.
• You have questions or concerns about your condition or care.

Medicines:

You may need any of the following:

• NSAIDs , such as ibuprofen, help decrease swelling, pain, and fever. This medicine is available with or without a doctor's order. NSAIDs can cause stomach bleeding or kidney problems in certain people. If you take blood thinner medicine, always ask your healthcare provider if NSAIDs are safe for you. Always read the medicine label and follow directions.
• Acetaminophen decreases pain and fever. It is available without a doctor's order. Ask how much to take and how often to take it. Follow directions. Read the labels of all other medicines you are using to see if they also contain acetaminophen, or ask your doctor or pharmacist. Acetaminophen can cause liver damage if not taken correctly.
• Prescription pain medicine may be given. Ask your healthcare provider how to take this medicine safely. Some prescription pain medicines contain acetaminophen. Do not take other medicines that contain acetaminophen without talking to your healthcare provider. Too much acetaminophen may cause liver damage. Prescription pain medicine may cause constipation. Ask your healthcare provider how to prevent or treat constipation.
• Take your medicine as directed. Contact your healthcare provider if you think your medicine is not helping or if you have side effects. Tell your provider if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Care for the biopsy area as directed:

Ask your healthcare provider when the area can get wet. Carefully wash around the area with soap and water. It is okay to let soap and water gently run over the area. Do not scrub your skin. Gently pat the area dry and put on new, clean bandages as directed. Change your bandages when they get wet or dirty. If you have strips of medical tape, let them fall of on their own. It may take 10 to 14 days for them to fall off. Check the area every day for signs of infection, such as redness, swelling, or pus. Do not put powders or lotions on the area. If lymph nodes have been taken from your armpit, ask your provider when you can wear deodorant.

Self-care:

• Apply ice on your incision for 15 to 20 minutes every hour or as directed. Use an ice pack, or put crushed ice in a plastic bag. Cover it with a towel before you apply it to your skin. Ice helps prevent tissue damage and decreases swelling and pain.
• Elevate your arm or leg nearest to the biopsy site as often as you can. This will help decrease swelling and pain. Prop your arm or leg on pillows or blankets to keep it elevated above the level of your heart comfortably.
• Do not do strenuous activities for 24 to 48 hours. Strenuous activities include heavy lifting, sports, or running. If lymph nodes were taken from your armpit, do not push or pull with your arm. These activities may put too much stress on your incision. Rest and take short walks around the house. Ask your healthcare provider when you can return to your normal activities.
• Drink plenty of liquids as directed. This will help flush out contrast liquid from your body. Ask how much liquid to drink each day and which liquids are best for you.

Ask your healthcare provider how to prevent lymphedema and infection:

An infection in your skin can make lymphedema worse. Ask your healthcare provider how you can decrease your risk for skin infections and lymphedema.

Follow up with your doctor as directed:

Write down your questions so you remember to ask them during your visits.

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