Stereotactic Breast Biopsy
What is a Stereotactic Breast Biopsy?
Lumps or abnormalities in the breast are often detected by physical examination, mammography or other imaging studies. However, it is not always possible to tell from these imaging tests whether a growth is benign or cancerous.
A breast biopsy is performed to remove some cells (surgically or through a less invasive procedure involving a hollow needle) from a suspicious area in the breast and examine them under a microscope to determine a diagnosis. Image-guided needle biopsy is not designed to remove the entire lesion, but most of a very small lesion may be removed in the process of biopsy.
In stereotactic breast biopsy a special mammography machine uses ionizing radiation to help guide the radiologist's instruments to the site of the abnormal growth.
What Are Some Common Uses of the Procedure?
A stereotactic breast biopsy is performed when a mammogram shows a breast abnormality such as:
- A suspicious solid mass.
- Microcalcifications (a tiny cluster of small calcium deposits).
- A distortion in the structure of the breast tissue.
- An area of abnormal tissue change.
- A new mass or area of calcium deposits present at a previous surgery site.
Stereotactic breast biopsy is also performed when the patient or physician strongly prefers a non-surgical method of assessing a breast abnormality.
How Should I Prepare?
- You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, dentures, eyeglasses and any metal objects or clothing that might interfere with the X-ray images.
- Women should always inform their physician if there is any possibility that they are pregnant. Some procedures using image-guidance are typically not performed during pregnancy, because radiation can be harmful to the fetus.
- You should not wear deodorant, powder, lotion or perfume under your arms or on your breasts on the day of the exam.
- Before a needle biopsy, you should report to your doctor all medications you are taking, including herbal supplements, and if you have any allergies, especially to anesthesia. Your physician will advise you to stop taking aspirin or a blood thinner three days before your procedure.
- Inform your doctor about recent illnesses or other medical conditions.
- You may want to have a relative or friend accompany you and drive you home afterward. This is recommended if you have been sedated.
How Does the Procedure Work?
Mammography is a low-dose X-ray system designed to examine breasts. The special mammography unit used to perform a stereotactic breast biopsy is a digital mammography machine. In digital mammography, as in digital photography, electronic detectors replace film. These convert X-rays into electrical signals which are used to produce images of the breast that can be immediately seen on a computer screen.
Stereotactic mammography pinpoints the exact location of a breast mass by using a computer and X-rays taken from two different angles. Using these computer coordinates, the radiologist inserts the needle through the skin, advances it into the lesion and removes tissue samples.
How is the Procedure Performed?
A specially trained radiologist most often performs image-guided, minimally-invasive procedures such as stereotactic breast biopsy. Breast biopsies are usually done on an outpatient basis.
You will lie face down on a moveable exam table, and the affected breast or breasts will be positioned into openings in the table. The table is then raised and the procedure is then performed beneath it. If the machine is an upright system, you may be seated next to the stereotactic mammography unit. The breast is compressed and held in position throughout the procedure.
A local anesthetic is injected into the breast to numb it. Several stereotactic pairs of X-ray images are taken. A very small cut is made in the skin at the site where the biopsy needle is to be inserted. The radiologist then inserts the needle and advances it to the location of the abnormality using the X-ray and computer generated coordinates. X-ray images are again obtained to confirm the needle tip is actually within the lesion.
Using a core needle biopsy, the automated mechanism is activated, moving the needle forward and filling the needle trough (or shallow receptacle) with 'cores' of breast tissue. The outer sheath instantly moves forward to cut the tissue and keep it in the trough. This process is repeated three to six times.
After the sampling, the needle is removed. A final set of images is taken. A small marker may be placed at the site, so it can be located in the future if necessary. Once the biopsy is complete, pressure is applied to stop any bleeding, and the opening in the skin is covered with a dressing. No sutures are needed.
A mammogram may be performed to confirm that the marker is in the proper position. This procedure is usually completed within an hour.
What Will I Experience During and After the Procedure?
You will be awake during your biopsy and should have little or no discomfort. Most women report little or no pain and no scarring on the breast. Some women find that the major discomfort of the procedure is from lying on their stomach for the length of the procedure which can be reduced by strategically placed cushions.
When you receive the local anesthetic to numb the skin, you will feel a slight pin prick from the needle. You may feel some pressure when the biopsy needle is inserted. The area will become numb within a short time. You must remain still while the biopsy is performed. As tissue samples are taken, you may hear clicks from the sampling instrument.
If you experience swelling and bruising following your biopsy, you may be instructed to take an over-the-counter pain reliever and to use a cold pack. Temporary bruising is normal. You should contact your physician if you experience excessive swelling, bleeding, drainage, redness or heat in the breast.
If a marker is left inside the breast to mark the location of the biopsied lesion, it will cause no pain, disfigurement or harm. You should avoid strenuous activity for 24 hours after returning home. Then, you should be able to resume normal activities.
Who Interprets the Results and How Do I Get Them?
A pathologist examines the removed specimen and makes a final diagnosis. Either the radiologist or your referring physician will share the results with you.