PERCUTANEOUS CORE BIOPSY OF THE BREAST - EFFECT OF OPERATOR EXPERIENCE AND NUMBER OF SAMPLES ON DIAGNOSTIC-ACCURACY

OBJECTIVE. The purpose of our study was to assess the degree of operat or experience and the number of core biopsy samples required to achiev e an accurate histologic diagnosis for each of five common mammographi cally defined lesions, using percutaneous core breast biopsy performed on a dedicated prone biopsy table, SUBJECTS AND METHODS. A prospectiv e multisite study was performed that involved nine institutions (acade mic and private) with experienced breast radiologists and the use of d edicated prone biopsy table units with digital assistance and standard ized protocol, Asymptomatic women evaluated during a 2-year study peri od were assigned a mammographic diagnosis reported in a manner prescri bed by the American College of Radiology Breast Imaging Reporting and Data System lexicon, Mammographic lesions evaluated included masses, m asses with calcifications, clustered calcifications, focal asymmetries , and architectural distortions, Where histologic diagnosis was indica ted, core biopsy was performed with five individual samples obtained a nd sequentially analyzed, Two hundred thirty patients had immediate ex cisional biopsy, the results of which provided the basis for a statist ical analysis to compare the accuracy of each sequential core biopsy s ample with surgical results, Statistical analysis was also done to asc ertain the accuracy of core biopsy diagnosis as a function of operator experience, RESULTS. Trends toward increasing accuracy were observed by increasing the number of core biopsies for each of five types of ma mmographically defined lesions, especially for clustered calcification s, Statistically significant increased accuracy was observed when the number of biopsies was increased beyond one (p = .003), Trends toward increased accuracy with more experience were observed for all lesions, especially for calcifications, Of the 230 lesions studied with immedi ate surgical validation, more than 80% of all lesions except clustered calcifications (75%) were diagnosed on the basis of two core biopsies ; accuracy after five biopsies was 98% for masses, 91% for calcificati ons, 100% for masses with calcification, 100% for focal asymmetries, a nd 86% for architectural distortions, CONCLUSIONS. Accuracy of diagnos is based on the results of percutaneous core breast biopsy improved wi th an increase in the number of core biopsy samples obtained for any g iven lesion seen on mammograms and with increased experience in perfor ming the procedure, Five samples yielded an overall diagnostic accurac y of 97%, Familiarity with expected accuracy from this procedure for d ifferent mammographic lesions and following increased experience may a ssist physicians in planning patient management.