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Breast Cancer

Breast Needle Localization

​​What is needle localization?

Needle localization (also called wire localization) is a procedure done before breast cancer surgery to find where the breast abnormality is (The wire marks the spot) so that the surgeon knows exactly what tissue to take out.

This procedure is done by 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 will know where the tissue is that has to come out.

If you’re having the procedure done somewhere other than where you’re having the biopsy or surgery, please have someone drive you to the hospital where you’re having the biopsy or breast surgery afterwards. Don’t drive yourself. You can wear your shoulder seatbelt—it won’t move the wire in your breast.

Please wear a top that closes at the front to make it easier to dress after the wire is in position and so you don’t have to lift your arm after the wire is in position.

What happens during the needle localization?

  1. A mammogram or ultrasound is done to find the exact location for the needle/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 before placing the needle.
  4. A thin needle is then inserted into the breast, down to the area of concern. Most women feel some pressure when the locating needle goes in. Let the technologist know how you're feeling so that we 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 will help guide the surgeon.
  7. The wire is securely taped in place onto your skin so it doesn’t move out of position. Move the arm on the side with the wire as little as possible so there’s less chance that the wire will move out of place.

What happens after the needle localization?

  • Once the wire is in place, go to the:
    • Breast Health Clinic for the biopsy OR
    • hospital site where you're having your surgery
  • You'll be given either a local freezing (biopsy) or a general anesthetic (surgery).
  • Once the tissue around the wire is taken out, it’s sent for testing to both the x-ray department (to confirm the entire area has been taken out) and to the laboratory.


Ask your surgeon when you should make an appointment to go over your results. Make the appointment before you go home.​

Current as of: May 2, 2018

Author: Women’s Health, Alberta Health Services