UK NHSBSP multicentre image guided biopsy trial: an interim analysis

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There are no randomised control trials (RCT) evaluating the efficacy of 11-gauge Mammotome (Ma) to 14-gauge core biopsy (CB). The aim of the study is to compare the diagnostic accuracy of the two stereotactic biopsy techniques in the diagnosis of microcalcifications and architectural distortion. A total of 600 women with impalpable clustered microcalcifications and/or distortions are prospectively recruited in a multicentre (Edgware, King's, Nottingham, Cambridge) RCT. Lesions with associated mass or density are excluded. Specimen radiographs are obtained for all biopsies performed for microcalcifications. A total of 370 women have been recruited so far and complete data for 135 women analysed. Seventy-two CB and 63 Ma had been performed on 124 microcalcifications, two distortions with microcalcifications and nine distortions. There are 34 cancers (25%) consisting of five invasive and 29 in situ carcinoma. Comparing CB and Ma, the absolute sensitivity for malignancy was 47% and 76.4%, respectively (P = 0.07) with a complete sensitivity of 76.4% and 100%, respectively (P = 0.05). CB produced more inadequate results compared to Ma (13.9% versus 4.8%, respectively; P = 0.06). Calcification retrieval was successful in 95% cases using Ma compared to 85.1% using CB (P = 0.06). The preliminary findings indicate that the use of Ma biopsy is more likely to produce a diagnostic result in the assessment of clustered microcalcifications compared to CB.