Stereotactic Breast Biopsy
What is X-Ray Guided Breast Biopsy?
Mammography is an excellent way to detect breast abnormalities, but in many cases it is not possible to tell from the imaging studies alone whether a growth is benign or cancerous. To make this determination it is necessary to obtain a tissue sample for microscopic examination. As an alternative to open surgical biopsy, which removes an entire breast lump for microscopic analysis, a hollow needle may be passed through the skin into the suspicious lesion with the help of special breast x-rays. The small sample of breast tissue obtained in this way can show whether the lesion is malignant or benign, and the procedure is much less invasive than the surgical approach. A special computerized mammography machine uses intersecting coordinates to pinpoint the area of tissue change. This method is called stereotactic biopsy or x-ray-guided biopsy. A pathologist examines the obtained specimen and makes a final diagnosis so that treatment planning can begin.
This special apparatus permits the doctor to perform a mammogram that displays as a digital readout on a computer screen. Once the suspect area is located, the computer logarithmically calculates the spatial orientation of the tissue in 3 dimensions, permitting the physician to pinpoint exactly its location in the breast.
The doctor is able to perform a needle biopsy – the extraction of suspect tissue for pathological examination – without the patient having to move from the examination table.
What are some common uses of the procedure?
A stereotactic breast biopsy is most helpful when mammography shows a mass, a cluster of microcalcifications (tiny calcium deposits that are closely grouped together), or an area of abnormal tissue change, but no lump can be felt on careful breast examination. A core biopsy is performed using a vacuum assisted needle biopsy device. This system uses gentle suction to obtain a tissue sample. This is less invasive than a surgical biopsy.
X-ray images also are used to place a guide wire into the suspicious area in order to help locate the lesion during open surgical biopsy, which is performed in an operating room.
An x-ray-guided biopsy often is done when:
- A woman has a mammogram showing a suspicious solid mass that cannot be felt on breast examination.
- A woman has a mammogram showing a suspicious cluster of small calcium deposits.
- The structure of the breast tissue is distorted.
- A new mass or area of calcium deposits is present at a previous surgery site.
How should I prepare for the procedure?
Even though most women who have a breast biopsy are found not to have cancer, despite an abnormality on the mammogram, you may want to have a relative or friend join you to lend support and to drive you home. If you are taking aspirin or a blood thinner, you will need to stop taking these five days in advance of the biopsy. Be sure to check with your physician before discontinuing your medication.
What does the equipment look like?
The patient is lying face-down with her breast projecting through a hole in the table. The actual biopsy is done below the table after raising it to gain access to her breast.
A paddle-shaped instrument compresses the breast during biopsy. A tray is nearby, containing all of the equipment necessary for the biopsy.
How does the procedure work?
In addition to the specialized equipment needed for x-ray-guided breast biopsy, specially trained technologists and physicians perform the procedure. The principle of stereotactic biopsy is that a lesion can be located precisely in three dimensions by calculating its apparent change in position on angled x-ray images. The first x-ray locates the abnormality in the breast, after which two stereo views are obtained, each angled 15 degrees to either side of the initial image. The physician then marks the lesion electronically on the stereo images. The computer calculates how much the lesion's position appears to have changed on each of the stereo views, and in this way is able to determine its exact site in three-dimensional space.
The vacuum assisted biopsy device, the VAD, uses vacuum pressure to pull breast tissue into a needle and remove it without having to withdraw the needle after each sampling. Another advantage of this device is that biopsies are obtained in an orderly manner by rotating the probe, assuring that the entire region of interest will be sampled. Using the automated core biopsy needle, sampling is more random.
How is the procedure performed?
The first step is to clean the skin with Chlor-prep and inject a local anesthetic. A small nick is made in the skin and the tip of the biopsy needle is advanced to the calculated site of the lesion. At this point stereo images are again obtained to confirm that the needle tip actually is within the lesion. Usually 5 to12 samples are collected when doing a biopsy. Then a final set of images is obtained. If they show that the lesion has been mostly or completely removed, a small clip is left at the biopsy site so that it can be easily located if the biopsy results are abnormal. Afterwards the skin opening is covered with a dressing; it need not be sutured. You will be told to avoid strenuous activity for 24 hours after returning home, but then will usually be able to resume normal activities. You will need to keep the area dry the rest of the day and keep an ice pack on the area for 2-4 hours post procedure.
What will I experience during the procedure?
X-ray-guided breast biopsy can take from 30 to 60 minutes or more. Most women report little or no pain, and no scar is left from the tiny skin incision. Many women find the major discomfort of the procedure is from lying on their stomach for the length of the procedure. You may take Tylenol after the procedure for any discomfort.
Who interprets the results and how do I get them?
A diagnosis requires processing numerous, high-quality slides over a period of 48-72 hours . When your biopsy findings are ready you may have a session with your physician to discuss the results and decide on the next step. If an abnormality is found, you may be referred to a surgeon or tumor specialist.