Originally published by Harvard Health.
What is the test?
Stereotactic biopsy of the breast is a special type of large core needle biopsy. It is one method of guiding the biopsy needle to the desired location in the breast. Core needle biopsy can also be guided by ultrasound or by the standard x-ray techniques used in mammography. Large core needle biopsy is often the diagnostic method of choice to evaluate abnormalities that are visible on a mammogram but cannot easily be felt by hand.
Core needle biopsy may not be suitable for women who have:
- An irregularity close to the chest wall, the nipple, or the surface of the breast
- Certain types of calcium deposits in the area of concern
- Very small breasts
In these situations, accurate results from a core needle biopsy may not be possible. Instead, your doctor may recommend a surgical biopsy.
How do I prepare for the test?
If you take blood thinners, aspirin or NSAIDs, you might have to stop using them for several days before the test to avoid bleeding complications. If you’ve had an allergic reaction to lidocaine or a similar local anesthetic, let your doctor know this before having the test.
What happens when the test is performed?
You wear a hospital gown that is open in the front. The needle used during a core biopsy is about as thick as a pen tip. It usually is placed into the breast through a tiny incision that has been made in the skin of the breast. Using mammogram or ultrasound images as a guide, or by feeling the lump, the doctor moves the needle into the area of concern. He or she removes one or more tissue samples through the needle with the help of suction from a syringe.
For a stereotactic biopsy, you’ll lie on your stomach on a special x-ray table. This table has an opening that allows your breast to hang down during the procedure. An x-ray (mammogram) is taken, and a computer determines the position of the suspicious tissue inside your breast. Then, the computer guides the tip of the biopsy needle directly to the suspicious tissue. The doctor makes only a single puncture in the skin to extract tissue samples for analysis. You should feel pressure but not pain.
Although the biopsy itself takes only a few minutes, the entire stereotactic procedure takes 20-40 minutes. Women who cannot remain still for that long because of physical illness or other problems are not good candidates for stereotactic core needle biopsy.
What risks are there from the test?
After the biopsy, you might have a small amount of bleeding or bruising and some breast soreness. This procedure leaves only a tiny dot for a scar.
Must I do anything special after the test is over?
No. After a core needle biopsy is completed, the doctor may place a bag of ice on the site for 15-30 minutes. Most likely, you’ll be able to resume normal activity almost immediately afterward.
How long is it before the result of the test is known?
Examination of the biopsy sample usually requires several days. At centers where physicians are experienced in these biopsies, 65% of women who undergo this procedure are diagnosed with a benign condition and can resume having annual mammograms. Another 25% have a malignancy or a premalignant condition and proceed with treatment. For the remaining 10%, results are inconclusive; in most of these cases, the next step is a surgical biopsy.