Diagnostic accuracy of stereotactic core-needle biopsy of non-palpable breast lesions categorized as BI-RADS® 4

PURPOSE: to assess the accuracy (rate of correct predictions) of stereotactic core needle biopsy (CNB) of risk category BI-RADS® 4 breast lesions. METHODS: a retrospective analysis of category BI-RADS® 4 breast lesions that had been submitted to a stereotactic core-needle biopsy from June 1998 to June 2003. Patients with histological benign results consistent with the radiographic image were referred to mammographic follow-up. Patients with malign diagnosis and papillary lesions were submitted to standard specific treatment. Excisional biopsies were performed when results were benign, but in disagreement with the mammographic image. It was considered as a gold-standard attendance: (1) the mammographic follow-up of low suspicion lesions with benign results at CNB, which stayed unchanged for, at least, three years, and (2) surgical resection when specimen results were malign or benign, but with a high suspicion on mammography. Sensitivity (S) specificity (E) and overall accuracy of stereotactic CNB were statistically analyzed. RESULTS: among the 118 non-palpable lesions of category BI-RADS® 4 submitted to CNB, the results obtained were: 27 malign cases, 81 benign, and ten lesions with atypical or papillary lesions. The statistical analysis comprised 108 patients (atypical and papillary lesions were excluded). CNB sensitivity was 87.1% and specificity 100%. The positive predictive value was 100% and the negative, 95.1%. False negatives occurred in 3.7% (4/108) of cases. The prevalence of malign diagnostics in the BI-RADS® 4 lesions of this sample was 29.7 (31/118). The accuracy of this method in this casuistic was 96.3%. CONCLUSIONS: these results support stereotactic CNB as an extremely reliable alternative to open biopsy, in the diagnosis and definition of breast lesions. In positive results, it is possible to indicate the appropriate therapy, and, in negative (when mammography shows low suspicion), it allows a follow up.