Analysis of false-negative results after US-guided 14-gauge core needle breast biopsy

Objectives: To determine the false-negative rate and to evaluate the clinical, radiologic or histologic features of false-negative results at ultrasound (US)-guided 14-gauge core needle biopsy (CNB). Methods: A total of 3,724 masses from 3,308 women who had undergone US-guided 14-gauge CNB and who had a rebiopsy or at least 2 years' follow-up were included. The histology of CNB was correlated with the rebiopsy or long-term imaging follow-up. In cases of missed cancer, the time interval between CNB and rebiopsy, the reasons for rebiopsy, and the procedural or lesion characteristics were analysed. Results: Of 1,706 benign CNBs, 50 additional malignancies were found at excision (false-negative rate, 2.5% of 1,982 with a final diagnosis of malignancy). Of 50 false negatives, 41 were found immediately of which 28 had rebiopsy because of imaging-histological discordance. Regarding the frequency of malignancy according to the reasons for rebiopsy, suspicious imaging finding (24%) showed significantly higher frequency than suspicious clinical findings or request (1%). Regarding the characteristics except invasiveness, no significant differences in false-negative rates were found. Conclusions: Most false negatives were found immediately and imaging-histological discordance was the most important clue. Careful correlation of clinical, radiological and histological results as well as appropriate follow-up is essential.