Surgeon interpretation of margin status utilizing intraoperative 3D tomosynthesis during breast-conserving surgery

Obtaining negative margins at the time of segmental mastectomy (SM) is important to reduce risk of local recurrence and avoid the need for a second surgery due to positive margins. Our current institutional standard practice (ISP) includes intraoperative assessment of the gross specimen and specimen radiographs by a multidisciplinary team including radiologists and pathologists.

In this study, we utilized digital breast tomosynthesis (DBT) images of SM specimens in the operating room and recorded when additional (selective) shave margins were proposed by the surgeon. A breast radiologist later reviewed the archived DBT images. The timing and accuracy of surgeon and breast radiologists' margin assessment using DBT was then compared to our ISP.

There were 193 patients enrolled and included in the analysis. Of 196 SM specimens, 9.7% (n = 19) had positive margins prior to excision of selective shave margins. Of these, 16 were identified by ISP with a sensitivity of 84%, specificity of 29%, false-negative rate (FNR) of 16%, positive predictive value (PPV) of 11%, and negative predictive value (NPV) of 95%. Surgeon assessment of DBT images identified 16/19 specimens with positive margins, with a sensitivity of 84% (p > 0.05), specificity of 49% (p < 0.001), FNR of 16% (> 0.05), PPV of 15% (p > 0.05), and NPV of 97% (p > 0.05). The median time for surgeon interpretation was 6 (range 2-35) minutes vs. 33 (range 15-88) for ISP.

Surgeon interpretation of DBT images offers an alternative to a more time- and labor-intensive ISP for detecting positive margins during breast-conserving surgery, with comparable accuracy and higher sensitivity.