Stereotactic Vacuum-Assisted Breast Biopsy in Ductal Carcinoma in situ: Residual Microcalcifications and Intraoperative Findings.

Purpose: The question of overtreatment of ductal carcinoma in situ (DCIS) was raised because a significant proportion of especially low-grade DCIS lesions never progress to invasive cancer. The rationale for the present study was to analyze the value of stereotactic vacuum-assisted biopsy (VAB) for complete removal of DCIS, focusing on the relationship between the absence of residual microcalcifications after stereotactic VAB and the histopathological diagnosis of the definitive surgical specimen.

Patients and methods: Data of 58 consecutive patients diagnosed with DCIS by stereotactic VAB in a single breast center between 2012 and 2017 were analyzed. Patient records from the hospital information system were retrieved, and mammogram reports and images as well as histopathology reports were evaluated. The extent of microcalcifications before and after biopsy as well as the occurrence of DCIS in biopsy and definitive surgical specimens were analyzed and correlated.

Results: There was no correlation between the absence of residual microcalcifications in the post-biopsy mammogram and the absence of residual DCIS in the final surgical specimen (p = 0.085). Upstaging to invasive cancer was recorded in 4 cases (13%) but occurred only in the group that had high-grade DCIS on biopsy. Low-grade DCIS was never upgraded to high-grade DCIS in the definitive specimen.

Conclusions: The radiological absence of microcalcifications after stereotactic biopsy does not rule out residual DCIS in the final surgical specimen. Since upstaging to invasive cancer is seen in a substantial proportion of high-grade DCIS, the surgical excision of high-grade DCIS should remain the treatment of choice.