Objective: To compare the accuracy of 11-G vacuum-assisted biopsy (VAB) with 14-G core needle biopsy (CNB) to diagnose mammographic microcalcification (MM) and effect on surgical outcomes.
Methods: Following ethical approval, VAB and CNB (control) were compared in a randomized prospective study for first-line diagnosis of MM and subsequent surgical outcomes in two breast-screening units. Participants gave written informed consent. Exclusions included comorbidity precluding surgery, prior ipsilateral breast cancer and lesions >40 mm requiring mastectomy as first surgical procedure. The final pathological diagnosis was compared with the initial biopsy result. Quality-of-life (QOL) questionnaires were administered at baseline, 2, 6 and 12 months. 110 participants were required to show a 25% improvement in diagnosis with VAB compared with CNB (90% power).
Results: Eligibility was assessed for 787 cases; 129 females recalled from the National Health Service breast screening programme were randomized. Diagnostic accuracy of VAB was 86% and that of CNB was 84%. Using VAB, 2/14 (14.3%) cases upgraded from ductal carcinoma in situ to invasion at surgery and 3/19 (15.8%) using CNB. Following VAB 7/16 (44%) cases required repeat surgery vs 7/24 (29%) after CNB. Both groups recorded significant worsening of functional QOL measures and increased breast pain at follow-up.
Conclusion: VAB and CNB were equally accurate at diagnosing MM, and no significant differences in surgical outcomes were observed.
Advances in knowledge: The first randomized controlled study of VAB for diagnosis of microcalcification using digital mammography showed no difference in diagnostic accuracy of VAB and CNB, or in the proportion of participants needing repeat non-operative biopsy or second therapeutic operation to treat malignancy.