Lumpectomy Specimen Radiography: Does Orientation or 3D Tomosynthesis Improve Margin Assessment?

Abstract

Objective: To determine 1) whether 2 orthogonal oriented 2D views of excised breast cancer specimens improves surgical margin (SM) assessment compared to a single unoriented 2D view and 2) whether 2 orthogonal oriented views using 3D tomosynthesis improves SM assessment compared to 2 orthogonal oriented 2D views. Methods: 41 specimens were imaged using four protocols: single view unoriented 2D image acquired on a specimen unit (1VSU), two orthogonal oriented 2D images acquired on the specimen unit (2VSU), two orthogonal oriented 2D images acquired on a mammogram unit (2V2DMU), and two orthogonal oriented 3D images acquired on the mammogram unit (2V3DMU). Three breast imagers retrospectively and randomly assessed SM of the 41 specimens with each protocol. SM per histopathology was considered the gold standard. Results: The average area under the curve (AUC) was 0.60 for 1VSU, 0.66 for 2VSU, 0.68 for 2V2DMU, and 0.60 for 2V3DMU. Comparing AUCs for 2VSU vs. 1VSU by reader showed improved diagnostic accuracy using 2VSU, however this difference was only statistically significant for reader 3 (0.73 vs. 0.63, p = 0.0455). Comparing AUCs for 2V3DMU vs. 2V2DMU by reader showed mixed results, with reader 1 demonstrating increased accuracy (0.72 vs. 0.68, p = 0.5984) while readers 2 and 3 demonstrated decreased accuracy (0.50 vs. 0.62, p = 0.1089 and 0.58 vs. 0.75, p = 0.0269). Conclusions: 2VSU showed improved accuracy in SM prediction compared to 1VSU, although this was not statistically significant for all readers. 3D tomosynthesis did not improve SM assessment.