Objective: To determine the false negative and underestimation rates of stereotactic 14-gauge automated core needle breast biopsy (CNB) in Phramongkutklao Hospital.

Materials and Methods: A retrospective review of 124 breast lesions receiving stereotactic 14-gauge automated CNB, with either subsequent surgical excision or complete 2-year mammographic follow-up to confirm benignity was performed. The false negative rate and underestimation rate of both high-risk lesions and ductal carcinoma in situ (DCIS) were calculated.

Results: The 124 lesions presented as microcalcifications. CNB revealed 80 benign, 13 high risk (seven papillomas, five atypical ductal hyperplasia, and one atypical gland proliferation), and 31 malignant lesions. One of the 37 lesions that had a final diagnosis of carcinoma was benign at CNB, a false negative rate of 2.7%. Three of the five atypical ductal hyperplasia (60%) and two of the seven papillomas (28.6%) turned out to be cancer at surgical excision, while two of the 20 DCIS (10%) had invasive component at final diagnosis.

Conclusion: The false negative rate of stereotactic 14-gauge automated CNB of microcalcifications in Phramongkutklao Hospital was 2.7%. The underestimation rates of atypical ductal hyperplasia, papilloma, and DCIS were 60%, 28.6%, and 10%, respectively.

Keywords: Stereotactic biopsy, 14-gauge automated core needle, breast lesions, breast cancer, false negative rate, underestimation rate.

Received 5 Apr 2019 | Revised 4 Sep 2019 | Accepted 9 Sep 2019