A study from Division of Surgical Oncology, Department of Surgery, The University of Texas Southwestern Medical Center, Dallas, TX

Background: Intraoperative specimen radiographs performed during breast conservation surgery for cancer reduces the need for re-excision for positive margins. We studied 2D versus 3D image-guided cavity margin excision and compared it to final pathology and need for additional surgery.

Methods: We conducted a retrospective review of 657 breast-conserving operations performed for cancer from 2013 to 2018. Procedures were performed by four surgeons at a single tertiary institution with access intraoperatively to 2D and 3D radiographs. Data collected included demographics, intraoperative margin assessment, final pathology, and re-excision rates.

Results: A total of 466 patients had 2D and 191 had 3Dspecimen imaging. The 2D group had a lower mean age and a higher body mass index and proportion of minority patients than the 3D group (P \ 0.01). In the 3D group, there was a higher percentage of patients with mammographically denser breasts (P \ 0.06); 58% of patients in the 3D group had additional imaging-directed cavity margins excised versus 32% of patients in the 2D group (P\0.01). In the 2D group, 44 patients (9%) had positive final margins versus 8 patients (4%) in the 3D group (P = 0.02). No difference was found on total volume of excision (P =0.56). The re-excision rate for the 2D group was 11%versus 5% for the 3D group (P = 0.02; adjusted odds ratio =0.41, 95% confidence interval 0.19–0.86).

Conclusions: Re-excision rates using both modalities are low. A lower re-excision rate is independently associated with 3D tomosynthesis. This allows surgeons to excise additional margins at the index operation, decreasing reoperations and anxiety/costs for patients.

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