Underestimation of Ductal Carcinoma In Situ and Invasive Ductal Carcinoma in Specimens Obtained with Stereotactic-Guided Vacuum-Assisted Biopsy

Objective: We sought to determine the underestimation rates of ductal carcinoma in situ (DCIS) and of invasive ductal carcinoma (IDC), diagnosed as atypical ductal hyperplasia (ADH) and DCIS, respectively, occurring with stereotactic-guided vacuum-assisted breast biopsy (VABB) of suspicious microcalcifications. Methods: We retrospectively reviewed cases of ADH and DCIS diagnosed by stereotactic-guided VABB between 2010 and 2019 in our institution. The biopsy results were correlated with the subsequent surgical histopathology results. Results: A total of 44 ADH lesions and 83 DCIS lesions were sampled with stereotactic-guided VABB during the 10-year study period. All lesions were categorised as BI-RADS (Breast Imaging Reporting and Data System) 4. Most lesions had either 6 or 12 cores taken during the biopsy. The upgrade rate of VABB-diagnosed ADH was 18.2% (7 upgraded to DCIS and 1 to IDC out of 44 VABB diagnoses of ADH), while that of VABB-diagnosed DCIS was 9.6% (8 upgraded to IDC out of the 83 biopsy-diagnosed DCIS). Amorphous calcifications in ADH lesions were associated with a lower rate of malignancy upgrade (p = 0.019). No other predictors of upgrade for either ADH or DCIS were identified. When the pathology results of specimens without visible microcalcifications were reviewed separately, we found a very low rate of upgrade in the absence of histological microcalcifications or in the presence of a benign pathologic entity. Conclusion: A significant proportion of stereotactic-guided VABB-diagnosed ADH and DCIS were underdiagnosed when compared to surgical histopathology. Surgical excisional biopsy is recommended for all VABB-diagnosed ADH and DCIS lesions for definitive pathology.