Breast microcalcifications: retrieval failure at prone stereotactic core and vacuum breast biopsy--frequency, causes, and outcome

PURPOSE: To retrospectively determine the frequency and causes of failure to retrieve microcalcifications in nonpalpable lesions, as judged on a radiograph of the specimen, and to determine outcome in patients with those lesions. MATERIALS AND METHODS: Informed consent was obtained from each patient prior to biopsy. The institutional review board approved this HIPAA-compliant study and granted a waiver of informed consent. Retrospective review was performed of 1701 consecutive nonpalpable microcalcification lesions in 1511 women aged 29-92 years (median age, 54 years) who underwent percutaneous stereotactic biopsy on a prone biopsy table. Biopsy was successively performed with 14-gauge core, 14-gauge vacuum, and 11-gauge vacuum devices, with mild selection bias, and for each lesion, biopsy was performed with one device. Radiographs of the specimen were obtained to see whether microcalcifications were retrieved. Patient, mammographic, and biopsy variables were correlated with negative radiographs of the specimen. At repeat biopsy or mammographic follow-up, outcome was evaluated in patients with benign histologic results and negative radiographs of the specimen by using Fisher exact test P values. RESULTS: Radiographs of the specimen were negative in 16% (30 of 182) of lesions at 14-gauge core biopsy, in 4% (four of 96) of lesions at 14-gauge vacuum biopsy, and in 1% (19 of 1423) of lesions at 11-gauge vacuum biopsy (P < .001). Substantial bleeding was a significant factor (P < .001) in failure to retrieve microcalcifications at only 11-gauge vacuum biopsy. Histologic results in 53 lesions with negative radiographs of the specimen were malignant (n = 6), indicated atypical hyperplasia (n = 6), or were benign (n = 41). Follow-up in patients with 40 benign lesions was performed with repeat biopsy (n = 17, with malignancy in three lesions) or mammography (n = 23) for 15-128 months (median, 70 months); one patient with one lesion was lost to follow-up. CONCLUSION: Failure to retrieve microcalcifications was least common with 11-gauge directional vacuum-assisted biopsy and occurred in 1% (19 of 1423) of lesions. Cancer was missed in 8% (three of 40) of benign lesions in patients who were followed up.