UK National Health Service Breast Screening Programme (NHSBSP) multicentre image guided biopsy trial: an update

This is an update on randomised control trials (RCTs) evaluating the efficacy of 11-gauge mammotome (Ma) to 14-gauge core biopsy (CB). A total of 614 women with impalpable clustered microcalcifications and/or distortions were prospectively recruited in a multicentre (Edgware, King's, Nottingham and Cambridge) RCT. Specimen radiographs were obtained for all biopsies performed for microcalcifications. Complete data for 585 women were analysed. Two hundred and ninety-three CB and 292 Ma had been performed on 554 microcalcifications, two distortions with microcalcifications and 29 distortions. There are 191 cancers (32%) consisting of 54 invasive and 137 in situ carcinoma. Comparing CB and Ma, the absolute sensitivity for ductal carcinoma in situ (DCIS) was 79.2% and 80%, respectively, with a complete sensitivity of 89.6% and 96.6%, respectively (P = 0.1). The absolute sensitivity for invasive disease is 33.3% and 58.3%, respectively (P = 0.06). Mammotomy is significantly less likely to under-stage malignant disease when a B3 result is obtained compared to CB (17.5% versus 64%, respectively). The analysis suggests that the greatest benefit of mammotomy is in clustered microcalcification with an indeterminate appearance and in minimising the under-diagnosis of associated malignant disease.