Background: Needle core biopsy (NCB) is frequently used in the assessment of screen-detected breast lesions. NCB results are reported by the ‘B’ classification, introduced by the NHS Breast Cancer Screening Programme in 2001. Uncertainty remains over the appropriate management of NCBs reported as ‘uncertain malignant potential’ (B3) or ‘suspicious of malignancy’ (B4). Currently all patients with a B3/B4 NCB result are discussed at a multidisciplinary meeting and potentially undergo excision biopsy. However, this approach to management leads to the majority of patients with B3 results having surgery for a benign condition. This study aims to analyse a large screening dataset to establish positive predictive values (PPVs) for malignancy on excision biopsy, for different classifications of B3 and for B4 NCBs.

Needle core biopsy (NCB) is frequently used in assessing screen-detected breast lesions. Uncertainty remains over appropriate management of NCBs reported as 'uncertain malignant potential' (B3) or 'suspicious of malignancy' (B4). This study aims to analyse a large screening dataset to establish positive predictive values (PPVs) for malignancy on excision biopsy, for different classifications of B3 and for B4 NCBs.