by Scholten A


A sentinel lymph node biopsy is to remove and test lymph nodes where cancer would spread first. Lymph nodes are pea-sized glands throughout the body. They help fight infection.

Lymph Node Biopsy
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Reasons for Procedure

A sentinel node biopsy is done before or after cancer surgery. It is done to:

  • See if cancer cells have spread from a tumor to nearby lymph nodes (sentinel nodes)
  • Help determine the stage of the cancer

Possible Complications

Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:

  • Excess bleeding
  • Problems from anesthesia
  • Infection
  • Damage to nearby structures
  • Lymphedema
  • Allergy to the dye

Things that may raise the risk of problems are:

  • Recent illness or long term diseases such as diabetes or obesity
  • Smoking
  • Drinking alcohol

What to Expect

Prior to Procedure

The care team may meet with you to talk about:

  • Anesthesia options
  • Any allergies you may have
  • Fasting before the biopsy, such as avoiding food or drink after midnight the night before
  • Current medicines, herbs, and supplements that you take and whether you need to stop taking them before the biopsy
  • Whether you need a ride to and from the biopsy
  • Tests that will need to be done before the biopsy


Depending on where the lymph node is, the doctor may give:

  • General anesthesia —you will be asleep.
  • Local anesthesia—the area will be numb.
  • Regional anesthesia—an area of the body will be numb.

Description of the Procedure

A blue dye, and often a radioactive tracer, will be injected into an area near the tumor. It may be done a few hours before the biopsy. The dye and tracer will travel from the tumor area to the sentinel nodes. This will also help show which nodes are the sentinel lymph nodes.

A small incision will be made. The sentinel node(s) will be removed. The removed node (s) will be checked for cancer cells. If cancer is found, the rest of the lymph nodes in that area will be removed.

If cancer is not seen in the sentinel node, it is unlikely that the cancer has spread to other lymph nodes. The other lymph nodes will not be removed.

How Long Will It Take?

The biopsy takes about 30 to 60 minutes. Surgery to remove the entire cancer takes longer.

Will It Hurt?

There may be some mild pain and discomfort after the biopsy. Medicines can help.

Post-procedure Care

After the biopsy, there may be a short stay at the care center. Many can go home the same day.

The lymph node will be sent to the lab for testing. The biopsy results will determine if more lymph nodes need to be removed. It can also help determine how severe the cancer is.

At Home

Most can return to normal activity in a few days.

Call Your Doctor

Call your doctor if you are not getting better or you have:

  • Signs of infection, such as fever and chills
  • Redness, swelling, excess bleeding, or discharge from the incision
  • Redness, warmth, swelling, stiffness, or hardness in the hands or feet
  • Dark or swollen fingers and toes
  • Lasting nausea and/or vomiting
  • Pain that you cannot control with the medicine
  • Problems breathing or chest pain
  • New or unexpected symptoms

If you think you have an emergency, call for medical help right away.


American Cancer Society 

National Cancer Institute 


Canadian Cancer Society 

Health Canada 


Qiu SQ, Zhang GJ, et al. Evolution in sentinel lymph node biopsy in breast cancer. Crit Rev Oncol Hematol. 2018;123:83-94.

Sentinel lymph node biopsy for breast cancer. EBSCO DynaMed website. Available at: Accessed September 23, 2021.

Sentinel lymph node biopsy: questions and answers. National Cancer Institute website. Available at: Accessed September 23, 2021.

Sentinel lymph node biopsy. Yale Medicine website. Available at: Accessed September 23, 2021.

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