Intraoperative Assessment of Final Margins with a Handheld Optical Imaging Probe During Breast-Conserving Surgery May Reduce the Reoperation Rate: Results of a Multicenter Study

Background: A multicenter, prospective, blinded study was performed to test the feasibility of using a handheld optical imaging probe for the intraoperative assessment of final surgical margins during breast-conserving surgery (BCS) and to determine the potential impact on patient outcomes. Methods: Forty-six patients with early-stage breast cancer (one with bilateral disease) undergoing BCS at two study sites, the Johns Hopkins Hospital and Anne Arundel Medical Center, were enrolled in this study. During BCS, cavity-shaved margins were obtained and the final margins were examined ex vivo in the operating room with a probe incorporating optical coherence tomography (OCT) hardware and interferometric synthetic aperture microscopy (ISAM) image processing. Images were interpreted after BCS by three physicians blinded to final pathology-reported margin status. Individual and combined interpretations were assessed. Results were compared to conventional postoperative histopathology. Results: A total of 2,191 images were collected and interpreted from 229 shave margin specimens. Of the eight patients (17 %) with positive margins (0 mm), which included invasive and in situ diseases, the device identified all positive margins in five (63 %) of them; reoperation could potentially have been avoided in these patients. Among patients with pathologically negative margins (>0 mm), an estimated mean additional tissue volume of 10.7 ml (approximately 1 % of overall breast volume) would have been unnecessarily removed due to false positives. Conclusions: Intraoperative optical imaging of specimen margins with a handheld probe potentially eliminates the majority of reoperations.