Screen-detected malignant breast lesions diagnosed following benign (B2) or normal (B1) needle core biopsy diagnoses.

Unlabelled: Breast needle core biopsy (NCB) is now a standard diagnostic procedure in the triple assessment of screen detected breast lesions. However, unlike fine needle aspiration (FNA) cytology, information on the miss rate including false-negative diagnoses (FN) of malignancy (benign 'B2' or normal 'B1' NCB with a malignant outcome) is limited.

Methods: A large series of NCBs (121,742) performed over an 8-year period has been studied to assess the frequency and causes of missing a malignant diagnosis on NCB and to evaluate their impact on patients' management in the screening service.

Screen-detected breast lesions with malignant needle core biopsy diagnoses and no malignancy identified in subsequent surgical excision specimens (potential false-positive diagnosis).

Although breast needle core biopsy (NCB) is now a standard diagnostic procedure in the triple assessment of screen-detected breast lesions, data on the false-positive diagnoses of malignancy (malignant NCB 'B5' with normal/benign surgery) are lacking. In this study, we have studied a large series of NCBs (101,440) to assess the causes and pitfalls resulting in false-positive NCB diagnoses and to evaluate their impact on patients' management in the screening service. Our results showed that of 40,395 malignant NCBs reported during the period of this study, 174 NCBs are considered as false-positives (0.

Audit of performance of needle core biopsy diagnoses of screen detected breast lesions.

Breast needle core biopsy (NCB) is now a standard diagnostic procedure in the triple assessment of screen detected breast lesions. Therefore, it is important to provide robust and up-to-date data on the performance of NCB in the screening setting. However, previous studies of NCB have suffered from either limitation in the number of assessed cases or included a mix of symptomatic and screen detected breast lesions.