Abstract P1-16-05: Intra-operative imaging of surgical margins in breast conserving surgery using localized tissue dielectric response

Abstract

Abstract INTRODUCTION: Breast conserving surgery (BCS) removes the tumor with a surrounding margin of normal breast tissue, and to reduce local recurrence clear margins are needed. Involved margins identified by pathology several days later require a second operation. Between 20-40% of BCS patients require re-excision. There is a clear unmet clinical need for effective and efficacious intra-operative, real time assessment of breast tumor margins. The handheld, battery operated TOUCH Imaging device displays spatially resolved images of margins based on tissue spectral dielectric response. This novel imaging device enables surgeons to assess in real-time the status of the excised tissue margins. AIM: To determine the efficacy and safety of TOUCH Imaging device as used by surgeons during BCS and its health economics. METHOD: The 1st study of the TOUCH Imaging device was run in the USA with freshly excised breast tissue as part of BCS. The study was run in the pathology lab to determine the efficacy and safety of using the device. The efficacy was determined by surgeons interpretation of device generated margin images compared with permanent section pathology. A follow up study in the UK is currently underway. Surgeons were trained to use the device in the operating room on freshly excised tissue. The imaging was performed after the surgery was completed with no subsequent intervention. The margins were scored as clear or positive and the localization of the abnormality was marked using special ink for specific pathology attention. In the learning phase 18 BCS cases were performed. The main study is being run in two phases and is currently underway. Phase-1 aimed to determine the accuracy of the device when used by individual surgeons in real time had been completed. Analysis is on the way, and phase-2 will start following the confirmation of device accuracy and will involve using the device to direct intra-operatively which margins require further excision. Phase 2 will provide insight to the potential health economics of using the TOUCH Imaging device. RESULTS: Data from the first study in the USA on 50 BCS specimens, imaging 214 distinct margins are shown in the table. The sensitivity of the device is high; the false negative rate low, the specificity and false positive rates are satisfactory. TOUCH Compared to Permanent Section Pathology Positive PathologyNegative PathologyPositive TOUCH66 ( 30.8%)50 (23.4%))Negative TOUCH5 ( 2.3%)93 ( 43.5%) % (95% CI)% (90% CI)Sensitivity92.96 (84.33, 97.67)92.96 ( 85.76, 97.18)Specificity65.03 (56.62, 72.81)65.03 (57.93, 71.66)False Positive Rate34.97 ( 27.19, 43.38)34.97 (28.34, 42.07)False negative Rate7.04 ( 2.33, 15.67)7.04 ( 2.82, 14.24) The training study in the UK on 18 BCS specimen results showed 50% True Positive, 39% True Negative, 11% False Positive, 6% False Negative rates. There were 5 cases (28%) of positive margins < 1 mm and the device images identified 4 with 1 case (6%) being missed. Results from the ongoing study will be presented. CONCLUSIONS: • The TOUCH Imaging device is safe and efficacious. • It is easy for surgeons to use in the operating room. • This device has the potential to reduce BCS re-operation rate. Citation Format: J Michael Dixon, Lorna Renshaw, Oliver Young, Dhananjay Kulkarni, Talha Saleem, Moshe Sarfaty, Ramaswamy Sreenivasam, Catherine Kusnick, Jeremy Thomas. Intra-operative imaging of surgical margins in breast conserving surgery using localized tissue dielectric response [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-16-05.