Stereotactic biopsy of ductal carcinoma in situ of the breast using an 11-gauge vacuum-assisted device: Persistent underestimation of disease

OBJECTIVE. The purpose of this study was to compare the diagnostic accuracy of 14-gauge automated gun and 11-gauge directional vacuum-assisted biopsy techniques in the diagnosis of ductal carcinoma in situ of the breast. MATERIALS AND METHODS. We retrospectively reviewed 41 consecutive lesions t hat had been diagnosed as ductal carcinoma in situ using stereotactic needl e biopsy. The first 21 lesions had been biopsied using a 14-gauge automated gun; the remaining 20 lesions, using an 11-gauge vacuum-assisted device. S urgical histopathologic results at lumpectomy were compared with the findin gs at needle biopsy and defined as either concordant, when only ductal carc inoma in situ (i.e., no evidence of invasive carcinoma) was evident at surg ery, or discordant, when invasive carcinoma was found. One patient from the automated gun group was lost to follow-up and was not included in the anal ysis. RESULTS. Invasive carcinoma was found at surgery in seven (35%) of the 20 c ases diagnosed using the automated gun compared with three (15%) of the 20 cases diagnosed using the vacuum-assisted device (p =.13). In all three of these discordant vacuum-assisted cases, only microinvasive disease was foun d at surgery. However, in only two of the seven discordant automated gun ca ses was only microinvasive disease found at surgery. CONCLUSION. The 11-gauge directional vacuum-assisted biopsy technique may i mprove the accuracy of ductal carcinoma in situ diagnosis. Underestimation of disease still occurs, however.