Choice of Guidance Modality
Stereotactic guidance is preferable for lesions evident as calcifications, as well as for masses that cannot be identified with ultrasound. For masses that can be seen with ultrasound, ultrasound-guided biopsy is faster, less expensive and does not use ionizing radiation; therefore it may be the method of choice, in such cases if the appropriate equipment and expertise are available.
Although early work with image-guided biopsy was performed using fine needles, many centers have turned to larger tissue-acquisition devices because of the lower frequency of insufficient samples and the better characterization of benign and malignant lesions that is possible when a larger volume of tissue is obtained.
Previous studies of stereotactic core biopsy with a 14-gauge automated needle showed 87-96% concordance between results of stereotactic core biopsy and surgery. Complications were rare, with the frequency of hematoma and infection each approximately 1 in 1000.
A directional vacuum-assisted biopsy instrument is now available for performing imaging-guided biopsy, most often used with stereotactic guidance. Compared to the automated needle, the vacuum device acquires larger samples of tissue, has a higher frequency of retrieval of calcifications and may provide more accurate characterization of complex lesions such as those containing atypical ductal hyperplasia or ductal carcinoma in situ.
Choice of Tissue-Acquisition Device
Excellent results have been obtained using the 14-gauge automated needle for biopsy of masses under ultrasound or stereotactic guidance. For calcifications, several investigators have demonstrated a higher rate of calcification retrieval and more accurate lesion characterization using the directional vacuum-assisted biopsy probe than the automated needle.
The directional vacuum-assisted biopsy instrument may also be preferable for small lesions (e.g., 0.5 cm), because technology is available that allows accurate placement of a localizing clip through the biopsy probe to facilitate subsequent localization, if necessary. Further work is needed to determine if there is any benefit to the use of the larger biopsy cannulas that are now available.
Percutaneous biopsy is less invasive and less expensive than surgery. Less tissue is removed, so there is less resulting deformity in the breast and less scarring on subsequent mammograms. The biopsy can be performed rapidly, so there is less time lost from work or other activities.
Percutaneous biopsy is less expensive than surgery. Women who have percutaneous biopsy undergo fewer operations, regardless of whether the diagnosis is benign or malignant. Continued improvements in the technique for percutaneous biopsy will allow more women to take advantage of this alternative to surgery for the diagnosis of breast lesions.
Laura Liberman and Timothy L. Feng
Breast cancer detection demonstration project: five-year summary report. CA 2003