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Breast Cancer

Breast needle localization

​​Breast needle localization (also called wire localization) is a procedure done before breast cancer surgery or a breast biopsy​ to mark the area of concern in the breast.

This procedure is done under mammogram or ultrasound guidance. A fine, thread-like wire is placed as close as possible to the area of concern. With the wire in place, the surgeon knows exactly what tissue to take out.

What to wear

When you come to have this procedure, wear a top that closes at the front. This makes it easier to dress after the wire is in place because you won't have to lift your arm. 

During breast needle localization

  1. A mammogram or ultrasound is done to find the exact location for the needle and wire.
  2. Your breast is cleaned with a cool antiseptic solution.
  3. A small amount of local anesthetic (freezing) is sometimes injected to numb the skin.
  4. A thin needle is inserted into the breast, down to the area of concern. You may feel some pressure when the needle goes in. Tell the technologist how you're feeling so they can keep you as comfortable as possible.
  5. Another mammogram might be done to check that the needle is in the right position.
  6. The thin needle is taken out, leaving a thread-like wire hooked in place. The wire helps guide the surgeon.
  7. The wire is taped securely in place onto your skin so it doesn’t move. Try to keep the arm on the side with the wire as still as possible. Keeping that arm still makes it less likely the wire will move out of place.

After breast needle localization

Once the wire is in place, go to the breast health clinic for your biopsy or to the hospital where you're having your surgery.

If the clinic or hospital is in a different place than where you had breast needle localization, have someone drive you. Do not drive yourself. You can wear your shoulder seatbelt—it won't move the wire in your breast.

You'll be given either a local freezing for a biopsy or a general anesthetic for surgery.

Once the tissue around the wire is taken out, it’s sent for testing.


Ask your surgeon when to make an appointment to talk about your results. 

Make the appointment before you go home.​

Current as of: December 5, 2023

Author: Women’s Health, Alberta Health Services