Commentary (Parker)-Stereotactic Breast Biopsy: Indications and Results

A decade has passed since the first stereotactic-guided histologic breast biopsy was performed. Initially, the large-scale implementation of this technique met with a great deal of resistance from most surgeons, and more surprisingly, from many breast radiologists in academia.[1] Dershaw and Liberman were instrumental in reversing the steady stream of unsupported criticisms of this procedure that emanated from many centers across the United States. Rather than join their academic radiology colleagues in disparaging this new technique, they did what physician-scientists should do; they carefully and systematically performed a large number of clinical studies to determine whether or not the technique had merit.

Their present review article summarizes the substantial body of peer-reviewed work that supports the use of stereotactic-guided histologic needle biopsy of the breast. It is an excellent resource for those involved in the diagnosis and treatment of breast disease who wish to familiarize themselves with the current status and applications of stereotactic breast biopsy. Although this article is quite comprehensive, there are a few points worth expanding on, and some areas that need to be clarified.

Importance of Other Diagnostic Studies

First, it is important to note that stereotactic breast biopsy should not be used in a vacuum. Modern breast diagnosis requires the physician performing the diagnostic work-up and biopsy to have a large technologic armamentarium at his or her disposal. Physicians should not use or be allowed to perform stereotactic biopsy without immediate access to standard and magnification mammography units and high-quality breast ultrasound. The considerable problem-solving that frequently accompanies a stereotactic breast biopsy (especially if the patient is referred from an outside institution) requires immediate access to these instruments.

For example, a previously unsuspected focus of calcifications may require additional magnification views prior to selecting the best sites/approach for the biopsy. Additional areas of mammographic asymmetry may need spot compression. A scheduled biopsy may be avoided when additional diagnostic techniques prove that the area in question is truly benign and not in need of histologic sampling.

In addition, high-quality breast ultrasound is the best and sometimes only way to image many lesions, (such as masses seen on ultrasound for which only a vague mammographic density or ill-defined area of palpation raises concern), and this guidance modality should be used initially for those lesions. Also, during the course of a biopsy procedure, the need sometimes arises to switch from a stereotactic to an ultrasound-guided approach. It is clearly inappropriate to perform a stereotactic biopsy in a patient who would best be served by an ultrasound-guided biopsy merely because the necessary equipment or skills are unavailable.

Accuracy of Stereotactic Biopsy

The authors state that the "...accuracy of stereotactic core biopsy...is approximately 90%." Two of the four references supporting this statement involved the use of older, now inappropriate approaches to stereotactic breast biopsy. If modern techniques of core biopsy are evaluated (as in the authors’ references 23, 31, and 32), the accuracy should be 96% to 98%. Long-term (> 3 years) follow-up of the patients reported in reference 23 reveals a long-term false-negative rate of just over 3%.[unpublished data, Fred Burbank, April 1997].

Because of the improved correlation between mammotomy (vacuum-assisted, directional biopsy) and surgical excision for atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS), it can be extrapolated that there will be a substantially lower false-negative rate for patients undergoing mammotomy compared with core biopsy. In analyzing the false-negative data from the authors’ reference 23, it is clear that virtually all of the false-negatives for large core "gun" biopsy occurred in patients with calcified lesions and small (< 1 cm) masses.

Therefore, we now tailor our breast biopsies according to this information; ie, we use the mammotome for all stereotactic-guided breast biopsies (most of these are calcification cases) and for ultrasound-guided biopsy of small (< 1.5- cm) masses. For larger masses, we continue to use ultrasound-guided, large-core "gun" biopsies. This approach should be expected to be comparable to, if not better than, standard, needle- localized, surgical breast biopsy.

An additional comment on needle selection needs to made. We believe that there is no role for fine-needle aspiration (FNA) in the definitive diagnosis of breast lesions. A National Cancer Institute (NCI)-sponsored clinical trial on breast biopsy, Radiologic Diagnostic Oncology Group V (RDOG V), supports this assertion.[2]

Reconciling Histology With Prebiopsy Imaging

The final point I would like to make involves the authors’ statement that one should reconcile histologic findings with the prebiopsy imaging diagnosis. This is, indeed, a critical aspect of a percutaneous breast biopsy program. However, it should just be the first step in the patient follow-up regimen in such a program. Any physician or treatment center performing breast biopsies should be committed to an extensive (preferably automated) long-term patient follow-up and data collection system. In this way, no patient can "fall through the cracks," and the adequacy and appropriateness of a given biopsy program can be continually evaluated on the basis of outcomes. Ideally, a breast biopsy program should be linked to similar automated data collection systems for screening mammography, diagnostic work-up, and therapy, so that the entire process--from screening mammography through definitive histologic biopsy and subsequent treatment--can be easily monitored.

Thus, it is extremely important that stereotactic breast biopsy not be viewed in isolation, but rather, as an essential part of a patient-effective, cost-effective, high-quality approach to breast care. By conducting a plethora of clinical studies on stereotactic breast biopsy and communicating their own and others’ successful results in articles such as this one, Dershaw and Liberman have made extraordinary contributions toward ensuring that patients throughout the country have access to this essential component of modern breast care.

References:

1. Kopans DB: Caution on core. Radiology 193:325-328, 1994.

2. Pisano E, Tsimika J, Fajardo L, et al: Stereotactic fine needle aspiration (FNA) in the work-up of lesions detected by mammography: Insufficient sample rate across multiple centers in a nationwide trial. ACR Breast Conference, April 27-30, 1996, Dallas, Texas.