Freehand versus ultrasound-guided core biopsies of the breast: reducing the burden of repeat biopsies in patients presenting to the breast clinic.

In our breast unit a significant proportion of core biopsies are performed freehand sometimes necessitating a repeat biopsy under image guidance. The aims of this study were to establish the proportion of patients undergoing freehand core biopsies who proceeded to a repeat procedure and to determine any factors associated with a missed freehand biopsy. Four hundred and ten core biopsies over 21 months were included in the analysis. Demographic details, position and size of the lump, breast volume and lesion depth were recorded. Twenty-four percent freehand biopsies were repeated under ultrasound guidance. The histological classification of two-thirds of the repeat biopsies were upgraded, suggesting that the lesion had been previously missed. Multivariate analysis showed that missed freehand biopsies were strongly associated with deep lesions. If all lumps sited at a depth of 6mm or more were selected for US-guided core biopsy, the workload for the ultrasound department would increase by just less than a half and would have the effect of reducing the freehand biopsy miss rate by almost two-thirds. Core biopsies should be performed under ultrasound guidance. A freehand technique could be limited to superficial lesions. Depth is more predictive for a missed biopsy than lesion size or breast volume.