The role of micro-CT for intraoperative margin assessment of breast cancer

e13620 Background: Breast-conserving surgery (BCS) followed by radiotherapy requires adequate removal of the malignancy with a negative margin. Accurate pathologic margin status is not available intraoperatively and is found to be positive in up to 20% of cases, necessitating re-excision. Specimen mammography (SM), used to find a biopsy marker, may assist with margin status but is only 55% sensitive for Intraoperative margin assessment (IMA). IMA methods are being increasingly investigated. Because micro-computed tomography (micro-CT) produces three-dimensional volumetric images, we aimed to evaluate the diagnostic sensitivity of micro-CT for IMA. Methods: We performed a systematic review according to the PRISMA guidelines by querying Scopus, MEDLINE, EMBASE, PubMed, and Google Scholar through 12/21/22. (https://osf.io/342h8). Studies evaluating the applications of micro-CT scanning in breast cancer were included for systematic review, and those reporting the diagnostic indices of micro-CT for IMA compared to histopathologic results were incorporated in a study-level meta-analysis. A random effects coefficient binary regression model was used when a high level of heterogeneity was observed. Results: Of the 2920 studies, 18 studies were selected. IMA was reported in 7 studies (388 specimens), tumor size in 3 studies, microcalcifications in 12 studies, and sentinel lymph node assessment in 1 study. Half of the studies were performed in the USA; the participant’s ages ranged from 33 to 82 years, and the tumor size was between 0.8 and 55.8mm. Image procurement time ranged from 4 to 30 minutes. A pooled diagnostic sensitivity of 0.67 (95% CI: 0.48 – 0.82) and specificity of 0.75 (95% CI: 0.63 – 0.84) was revealed, and the pooled accuracy was calculated based on the normal-error estimation as 0.76 (95% CI: 0.69 – 0.83) for IMA by micro-CT compared to the histopathological evaluation. Conclusions: Micro-CT can create 3D images of the internal structure and vasculature in less than 30 minutes and detects up to 67% of positive margins intraoperatively, preventing a future reoperation. Although the results of this review are promising, due to the high level of heterogeneity, further investigations should be pursued as to how and who should report the images and whether micro-CT may have a role in IMA. [Table: see text]