PB.9. Randomised controlled trial of stereotactic 11G vacuum-assisted core biopsy for diagnosis and management of malignant microcalcification

Abstract

Background Vaccum-assisted biopsy (VAB) is claimed to improve diagnosis of malignant microcalcification (MM) and prevent underestimation of invasive component compared to stereotactic core biopsy (SCNB) 14g biopsies. VAB is also reported to reduce requirement for further surgical procedures versus SCNB. Methods In a randomised controlled trial, we compared both techniques in the firstline diagnosis of MM and subsequent surgical management in two UK Breast Screening Units. Patients with MM were identified and gave written informed consent to the study before randomisation 1:1 to SCNB or VAB. Exclusions included bleeding diathesis or significant comorbidity preventing surgery. SCNB was performed by advanced radiography practitioners and VAB by experienced radiologists under local anaesthesia. Quality of life was assessed using EORTC QLQ-BR23 questionnaire: Pre-biopsy, 2, 6, and 12 months post-randomisation. The primary objective compared the final pathological diagnosis with the initial biopsy (VAB or SCNB) and required 110 patients to be randomised to show a 25% improvement in diagnostic accuracy with VAB compared to SCNB with a 90% power. Results Three quarters of MM investigated was less than 15mm in size. Overall 787 women were investigated for eligibility. 476 did not meet the inclusion criteria, 82 declined to participate and 100 met exclusion criteria. In total, 129 women were randomised. Both groups were evenly matched for age 57.2 years (range 47-75) and lesion size but VAB took longer (p<0.001) and produced on average, 4 more cores (12 versus 8) (p<0.01). Three (4.7%) VAB developed bleeding causing procedure abandonment. The PPV for biopsy of MM was 30.2% and 1 patient withdrew before the procedure. There was an 84% diagnostic accuracy of SCNB which precluded any effect on surgical outcome. Both groups had significant Quality of Life (QOL) falls in Global Health (p<0.001) and Social Functioning over time (p<0.04) but no overall difference between groups was seen. At 12 months, body image scores fell and fatigue increased in patients undergoing surgery. Conclusion SCNB has equal accuracy as VAB in the firstline diagnosis of malignant microcalcification. Devicor provided the equipment to Dr S.B. and Prof. N.B., to do this study.