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Sentinel Lymph Node Biopsy: About This Test

What is it?

A sentinel lymph node biopsy is a surgery to take out lymph node tissue to look for cancer that has spread into the lymph system.

The lymph system is a network of vessels that carries material between the body tissues and the bloodstream. The sentinel lymph node is the first node in the body where cancer cells may be found if the cancer has spread from the original site.

Why is this test done?

This test is done to see if a cancer has spread from its original site. This information helps stage a cancer. The stage is a way for doctors to describe how far the cancer has spread. Your treatment choices will be based partly on the type and stage of cancer.

How do you prepare for the test?

  • Follow the instructions exactly about when to stop eating and drinking. If you don't, your test may be cancelled. If your doctor told you to take your medicines on the day of the test, take them with only a sip of water.
  • Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
  • Tell your doctor ALL the medicines and natural health products you take. Some may increase the risk of problems during your test. Your doctor will tell you if you should stop taking any of them before the test and how soon to do it.
  • If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your test. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.

How is the test done?

  • Your doctor injects a dye, a tracer, or both into your body near your cancer site. The dye stains the sentinel lymph node or nodes so they can be seen. The tracer travels to the sentinel lymph node where it can be detected.
  • Your doctor removes the sentinel node or nodes. The node is tested for cancer cells. The results help your doctor decide whether to remove any more nodes, either during the same surgery or at a later time.
  • You will have some stitches and a bandage over the biopsy site.

How long does the test take?

  • The biopsy usually takes 30 to 60 minutes. It may take longer if you have surgery to remove the cancer at the same time.

What happens after the test?

  • If you had 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.
  • The doctor will tell you what to do if you have any bleeding, numbness, or swelling at the biopsy site.
  • You might be able to go home the same day.
  • Your skin may be blue from the dye for several days after the test. The dye may also turn your urine green for 1 to 2 days.
  • Allow the area to heal. Don't move quickly or lift anything heavy until you are feeling better.
  • During your follow-up visit, your doctor will discuss the results of your biopsy with you and take out any stitches.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

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