False‐negative core needle biopsies of the breast

Abstract 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. Cancer 2003;97:1824–31. © 2003 American Cancer Society. DOI 10.1002/cncr.11278