Introduction

Breast cancer is a very common disease. It is the most common cancer in women. About one women in eight (12 percent 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 succesful 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 nonpalpable mammographic abnormalities. Presently, about 20% of breast biopsies are performed stereotactically. This is likely to increase to 75% of all mammographically discovered lesions within the next three years. The procedure has become popular because it is very accurate and it minimizes the surgical procedure.

Technique:The patient lies prone on the stereotactic table with the breast suspended through a hole in the table The breast is then placed in compression. Images are then obtained using digital x-rays. These x-rays 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 computer can then then help guide a biopsy needle to the exact coordinates of the lesion. 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 are taken (usually 6-10). The major advantage of the Mammotome procedure is that there is virtually no scar. The other type of stereotactic breast biopsy is called the ABBI procedure. This device removes a larger core of tissue (5-20mm). In this fashion, the entire lesion can be removed. This can sometimes provide a more accurate diagnosis. Both types of stereotactic breast biopsies are performed under local anasthesia. Patients have 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. They are as accurate as an open surgical biopsy. 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.