Stereotactic Breast Biopsy: A Study of First Core Samples

Stereotactic core needle biopsy (SCNB) is a sensitive and specific indicator of breast pathology. Commonly the first biopsy core is taken from the center of the lesion in question. Multiple cores are then taken from points peripheral to the central core. The sensitivity and specificity of the central core to diagnose breast disease is unclear. We compared the pathology of the central core biopsy with that of the remaining cores in a prospective study to determine the sensitivity and specificity of the central core to diagnose breast disease. All patients undergoing SCNB for breast lesions in a single surgical office during a 7-month period were eligible for inclusion. One hundred thirty-three patients with first cores from 145 biopsy sites were included. The histologic diagnosis from 117 (81%) of the first cores from these 145 biopsy sites were representative of their respective samples as a whole. Seventy-seven (53%) of the first cores were in complete agreement with the final histologic diagnosis whereas 40 (28%) had minor differences with the histologic diagnosis that had little or no clinical significance. Twenty-eight (19%) central core samples did not agree with the final pathologic diagnosis. Seven of these 28 patients each had a final diagnosis of cancer missed by the central core biopsy. The first core sample had a sensitivity for cancer detection of 79 per cent and specificity 100 per cent. SCNB remains a sensitive and specific identifier of breast pathology. When mammographic evidence of calcifications was the primary indication for SCNB (n = 75) calcification was present in the central core in 51 (68%). In these 51 patients the central core biopsy was in agreement with the final histologic diagnosis in 46 (90%) specimens. Histologic review of the first core sample alone lends no increased benefits and in fact misrepresents the pathology present in a significant number of patients. When analyzed as an independent predictor of breast pathology the first core is a more sensitive indicator than subsequent individual cores, but the most accurate predictor of pathology is examination of the entire group of core samples. This study confirms the need for acquisition of multiple cores from each lesion in question.