A sentinel lymph node biopsy is a surgery that takes out lymph node tissue to look for cancer. A sentinel node biopsy is used to see if a known cancer has spread from the original cancer site. A sentinel node biopsy may be done instead of a more extensive surgery called lymph node dissection. But if cancer is found in the sentinel lymph node at the time of surgery, more surgery may be needed to remove additional lymph nodes.
The sentinel lymph node is the first node in a group of nodes in the body where cancer cells may move to after they have left the original cancer site and started to spread. For example, the sentinel node (SN) for breast cancer is normally one of the lymph nodes under the arm.
Your doctor injects a blue dye or special tracer substance or both into the area around the original cancer site. The dye or tracer moves to the first lymph node (sentinel node) that drains close to the cancer site. The dye or tracer makes a map pattern of lymphatic fluid. The map can show where the cancer is likely to spread and which lymph node is most likely to have cancer cells. Your doctor can see the dye or tracer with a special device. The lymph node can be taken out, cut into very thin slices, and looked at under a microscope at the time of surgery. If a sentinel node is positive for cancer cells, more surgery may be needed to remove more lymph nodes.
Other tests, such as a culture, genetic tests, or immunological tests, may be done on the lymph node sample.
A sentinel lymph node biopsy is done to:
Tell your doctor if you:
Follow your doctor's instructions carefully. If you are given a medicine (sedative) to make you relax or sleep before the biopsy, do not eat or drink for 8 hours before the biopsy. Arrange for someone to drive you home after the biopsy.
Talk to your doctor about concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).
You will need to take off clothing near the biopsy site. You will wear a gown for a covering during the test.
If you are very anxious about the biopsy, you may be given a medicine (sedative) to help you relax.
Before a sentinel node biopsy is done, the dye or tracer is injected into the area, and a special camera (lymphoscintigraphy) takes pictures of the lymph nodes. Some doctors use pain medicine with the dye to reduce discomfort. The dye may turn your skin blue for a few days after the biopsy.
The first lymph node or nodes to absorb the tracer are called the sentinel nodes. This node or nodes and the tissue around them are taken out. You may have a numbing medicine (local anesthesia) or go to sleep for the biopsy. The lymph node sample is cut into many thin slices and looked at under a microscope for cancer. You will have some stitches and a bandage over the biopsy site.
A sentinel lymph node biopsy usually takes 30 to 60 minutes but may take longer. If you have general anesthesia, you will be watched by a nurse in the recovery room until you are fully awake.
Your doctor will give you specific instructions to take care of your biopsy site. During your follow-up visit, your doctor will discuss the results of your biopsy with you and take out your stitches.
You may feel a sharp sting or burn from the medicine used to numb the biopsy site or from the dye or tracer. Feeling pressure or warmth during the biopsy is normal, but you should feel little or no pain. If you have pain, tell your doctor. If you feel like you are having an allergic reaction, tell your doctor. This can happen with the dye used for this biopsy.
If you have general anesthesia, you may feel drowsy for several hours after the biopsy. You may have a mild sore throat from the tube used to help you breathe during the biopsy. Throat lozenges and gargling with warm salt water may help soothe your sore throat. You may get medicine at the biopsy site that will help with the pain for 6 to 12 hours. You may have more pain after this medicine wears off.
The biopsy site may be sore for several days. A small amount of bleeding is normal. Ask your doctor how much drainage to expect. Call your doctor immediately if you have:
It is possible to have some problems after a biopsy. Your doctor will give you instructions on what to do if a problem occurs.
The lymph node tissue is usually treated with special dyes (stains) that color the cells so problems can be clearly seen.
The dye or tracer flows evenly to the sentinel lymph node.
The lymph node has normal numbers of lymph node cells.
The structure of the lymph node and the cells look normal.
No cancer is present.
The dye or tracer does not flow evenly to the sentinel lymph node.
The sentinel lymph node cannot be identified.
Cancer cells may be seen. Cancer cells may start in the lymph nodes, such as in Hodgkin's lymphoma. Cancer cells may have spread, or metastasized, from other sites, such as in breast cancer or melanoma.
It may not be possible to have a clear result from the small sample taken during a sentinel lymph node biopsy. Surgery to remove more lymph nodes (axillary dissection) may be needed.
Other Works Consulted
- American Cancer Society (2010). Breast Cancer: Treating Breast Cancer. Available online: http://www.cancer.org/Cancer/BreastCancer/DetailedGuide/breast-cancer-treating-general-info.
- Cody HS (2010). Axillary dissection. In JR Harris et al., eds., Diseases of the Breast, 4th ed., pp. 562–569. Philadelphia: Lippincott Williams and Wilkins.
- National Cancer Institute (2011). Sentinel Lymph Node Biopsy. Available online: http://www.cancer.gov/cancertopics/factsheet/detection/sentinel-node-biopsy.
- Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Specialist Medical Reviewer C. Dale Mercer, MD, FRCSC, FACS - General Surgery
Current as ofJune 4, 2014
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