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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A sentinel node biopsy is done before or after cancer surgery. It is done to:
Problems are rare, but all procedures have some risk. The doctor will go over some problems that could happen, such as:
Things that may raise the risk of problems are:
The care team may meet with you to talk about:
Depending on where the lymph node is, the doctor may give:
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.
The biopsy takes about 30 to 60 minutes. Surgery to remove the entire cancer takes longer.
There may be some mild pain and discomfort after the biopsy. Medicines can help.
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.
Most can return to normal activity in a few days.
Call your doctor if you are not getting better or you have:
If you think you have an emergency, call for medical help right away.
American Cancer Society
National Cancer Institute
Canadian Cancer Society
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: https://www.dynamed.com/evaluation/sentinel-lymph-node-biopsy-for-breast-cancer. Accessed September 23, 2021.
Sentinel lymph node biopsy: questions and answers. National Cancer Institute website. Available at:
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Accessed September 23, 2021.
Sentinel lymph node biopsy. Yale Medicine website. Available at: https://www.yalemedicine.org/conditions/sentinel-lymph-node-biopsy. Accessed September 23, 2021.
Last reviewed July 2021 by
EBSCO Medical Review Board
Mohei Abouzied, MD, FACP
Last Updated: 9/23/2021