Evaluation of Breast Imaging Reporting and Data System Category 3 mammograms and the use of stereotactic vacuum-assisted breast biopsy in a nonacademic community practice.

BACKGROUND

Breast Imaging Reporting and Data System (BI-RADS) Category 3 represents 'probably benign' mammographic abnormalities requiring close follow-up, but biopsies sometimes are performed on Category 3 abnormalities. Controversy exists as to when these biopsies are justified. The goals of the current study were to evaluate the use of stereotactic vacuum-assisted breast biopsy (SVABB) for BI-RADS 3 lesions in a nonacademic community hospital-based practice, to evaluate the false- negative rate of Category 3 mammograms, and to determine whether any specific lesions misinterpreted as BI-RADS 3 abnormalities might commonly be associated with malignant disease.

METHODS

From August 2000 to December 2002, the authors performed 947 SVABB procedures on 911 patients. They focused on 156 SVABBs of BI-RADS 3 abnormalities.

RESULTS

Of 634 SVABB procedures requested by outside sources, 114 (18%) were performed for BI-RADS 3 abnormalities, compared with 42 (13%) of 313 SVABB procedures that were performed based on mammographic findings at the authors' practice (P = 0.075). After SVABB, 7 of 156 patients with BI-RADS 3 lesions were diagnosed with breast carcinoma and 1 was diagnosed with atypical ductal hyperplasia. Therefore, the false-negative rate of BI-RADS 3 mammograms was 4.5% (i.e., 7 of 156 patients). Patients with linear microcalcifications had the highest rate of cancer (4 of 14 [29%]) compared with patients without microcalcifications (1 of 64 [1.5%]) and patients with nonlinear microcalcifications (2 of 69 [2.9%]).

CONCLUSIONS

The use of SVABB for BI-RADS 3 lesions reflected uncertainty regarding the potential for a diagnosis of malignant disease rather than the financial incentive of performing a biopsy. SVABB was not necessary for patients with BI-RADS 3 lesions without microcalcifications or for patients with nonlinear microcalcifications. Lesions with linear (casting or branching) microcalcifications should not be considered BI-RADS 3 abnormalities.