Background: A benign diagnosis in a core needle biopsy (CNBx) of the breast performed for a clinically and/or radiologically suspicious abnormality is often due to a nonrepresentative sample. However, the discordance may not be recognized, resulting in a logistic delay in the diagnosis.
Methods: Twenty-seven false-negative CNBxs were identified in 952 consecutive CNBxs of the breast (653 benign, 266 malignant, and 33 atypical) performed during a 1-year period. Biopsies were analyzed with respect to clinical and radiologic findings, biopsy type, type of malignancy, and interval between the original CNBx and final diagnosis. Four hundred thirty-eight (67%) of the patients with a benign CNBx diagnosis either underwent excision or had a minimum of 1-year follow-up (mean, 35.6 months; median, 36 months).
Results: The cancers missed on CNBx included 6 ductal carcinomas in situ, 17 invasive ductal carcinomas, 3 invasive lobular carcinomas, and 1 non-Hodgkin lymphoma. The overall false-negative rate was 9.1%. For palpable lesions, ultrasound-guided CNBx had a lower rate of missed cancer (3.6%) compared with CNBx without image guidance (13.3%). The false-negative rate for vacuum assisted CNBx biopsy was 7.6% (3.3% for the 11-gauge needle, 22.2% for the 14-gauge needle; 5.6% for nonpalpable mass lesions, 8.2% for microcalcifications). In all seven false-negative CNBxs performed by radiologists, the discordance between the radiologic and pathologic findings was promptly recognized due to their standard follow-up protocol. The discordance between the degree of clinical suspicion, radiologic impression, and the pathologic findings was not immediately recognized in 5 of 20 false-negative CNBxs performed by surgeons (4 without radiologic guidance and 1 with ultrasound guidance), resulting in a delay in the diagnosis ranging from 112-336 days.
Conclusions: A false-negative diagnosis of breast carcinoma was found to be more common in CNBx performed without image guidance but occurred to a lesser degree in image-guided biopsies. A delay in diagnosis can be avoided by establishing a standard post-CNBx follow-up protocol.
Copyright 2003 American Cancer Society.