Stereotactic breast biopsy techniques and clinical applications

Stereotactic Breast Biopsy

Breast cancer is a very common disease, and is the most common type of cancer in women, although it is not unheard of for a man to have breast cancer. About one women in eight (12% of all women) will develop breast cancer at some time in her life. Approximately 50,000 women die from breast cancer every year. Early detection is an important factor in the successful treatment of breast cancer. Utilizing monthly self breast exams, periodic professional exams, and mammography breast cancer can usually be detected early. With early detection, breast cancer can be treated more effectively and patient outcomes improve. Mammograms are an essential part of this screening process. Although there is some controversy, the generally accepted recommendations for mammogram include a screening mammogram at age 35, annual mammograms every one or two years from age 40-50, and an annual mammogram after age 50. The mammogram does not make the diagnosis of cancer. It can show changes that may represent cancer. Often these changes are too small to be felt on examination. When these changes require a diagnosis, they have traditionally been removed with surgical excision following wire localization. The mammogram is used as a guide for placing a thin wire near the abnormality. The surgeon can then identify the area at surgery. The area around the wire is then removed in the operating room.

Stereotactic breast biopsy has been developed as an alternative to wire localized biopsy for mammographic abnormalities that cannot be felt with the hands. As of the date of this writing, about twenty percent of the breast biopsies done are performed stereotactically. It is believed that more and more breast biopsies will be performed stereotactically in the future. The procedure has become popular because it is very accurate and it minimizes the amount of cutting that has to be done to complete the surgical procedure.

How is the stereotactic biopsy done?

After the patient is identified as having a nonpalpable mass on mammogram, the patient is prepared for the procedure in the normal manner. Then the patient is made to line on her stomach on the stereotactic table with the breast suspended through a hole in the table The breast is then placed in compression, somewhat in the same manner as when she had the original mammogram. Images of the affected breast are then obtained using special digital x-rays which use much less radiation than traditional mammograms. Images are taken at two 15-degree angles from the center. The images are viewed on a computer monitor, and the physician can identify the lesion in three dimensions. The surgeon then uses the computer images to help him or her guide a biopsy needle to the exact coordinates of the abnormal area as indicated by the three dimensional picture. When the suspicious area is reached, the breast tissue can be removed in one of two ways. A large bore needle can be used to remove cores of tissue. This is called the Mammotome procedure. It removes cores of breast tissue via a small incision (2-3mm). Multiple cores samples are usually taken for this procedure. The major advantage of the Mammotome procedure is that there is virtually no scar. The other type of stereotactic breast biopsy is called the Advanced Breast Biopsy Instrumentation (ABBI) procedure. This device removes a larger core of tissue (5-20mm) and when this procedure us used then the entire lesion can be removed from the breast. The ABBI procedure can provide a more accurate diagnosis and also help to indicate if the entire suspicious area was removed. Both types of stereotactic breast biopsies are performed under local anesthesia, so the patient is awake during the whole things but report having minimal discomfort during or after the procedure. Patients can usually resume normal activities by the following day. Stereotactic biopsies have been shown to be very accurate. Studies done so far have shown that they can be as accurate as an open surgical biopsy, when performed by someone who is skilled in the procedure. Benefits of the procedure include less patient discomfort, quicker recovery, decreased scarring, and decreased cost. Traditional mammographic directed biopsies require that the lesion be seen on two views, but with stereotactic techniques abnormalities that are seen on one view can be removed. There are certain mammographic lesions that cannot be biopsied stereotactically. These include areas that are vague on the mammogram and might not show up on the digital screen as well as some areas of diffuse calcifications. Technical problems are sometimes seen in patients with small breasts or in lesions that are up against the chest wall. The decision as to whether a lesion can be removed stereotactically is usually made by the surgeon and the radiologist. As the procedure of stereotactic breast biopsy becomes more popular, more hospitals are obtaining the necessary equipment. Thus the technique is becoming available to the majority of patients with mammographically detectable lesions. Complications are rare and usually only include pain, localized swelling and the possibility of bleeding or infection.