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.