Abstract B021: Use of wide field optical coherence tomography (WF-OCT) in margin assessment during breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS)
Authors: Tower Amelia B. , Berkeley Andrew 
Published: December 2022

Abstract
Purpose: To assess the utility of a novel imaging technology for intraoperative margin assessment in breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS). Background: The multi-focal nature of DCIS presents a challenge to ensuring negative margins during BCS. Routine methods for intraoperative margin assessment, such as specimen radiography, ultrasound, cavity margins, and touch prep cytology each have specific limitations, including operator skill, time delay, probe position, and specimen completeness. A more recent method, wide field optical coherence tomography (WF-OCT), enables real-time tissue visualization at up to 2 mm of depth with the ability to use image-based machine learning to identify regions of interest suspicious for residual malignancy. Methods: Two adult females with biopsy-proven DCIS and one with invasive carcinoma underwent BCS following routine surveillance mammography and were prospectively evaluated. Primary lesions were imaged intraoperatively with specimen radiography and a WF-OCT imaging device (OTIS, Perimeter Medical AI, Toronto, Canada); images from both modalities were read to identify potential residual malignancy, and additional tissue was excised as indicated. Permanent histopathology was compared to imaging results. Results: The first patient (76 y/o, BI-RADS 4B, 1.6 cm) underwent BCS and the excised sample was 4 x 3.7 x 3.2 cm. By radiography, the biopsy clip and localization reflector were within the specimen and margins appeared satisfactory; WF-OCT demonstrated residual disease at the inferior margin and additional tissue was excised. Permanent histology showed DCIS involvement of inferior primary margin; additional margin excision contained DCIS and was negative. The second patient (64 y/o, BI-RADS 4B, 1 cm) underwent BCS and the excised sample was 4 x 3.5 x 3.5. By radiography, the biopsy clip and reflector were within the specimen and margins appeared satisfactory; WF-OCT showed residual disease at the inferior and posterior margins and additional tissue was excised. Permanent histology demonstrated DCIS within 1 mm and pleomorphic lobular carcinoma in situ (LCIS) microns from primary inferior margin; the additional inferior sample was margin negative, and posterior sample contained pleomorphic LCIS and was margin negative. The last patient (76 y/o, BI-RADS 5, 1.9 x 1.9 x 1.7 cm) underwent BCS and the excised sample was 6.5 x 5.3 x 4.2 cm. By radiography, the biopsy clip and localization reflector were within the specimen and margins appeared satisfactory; WF-OCT showed residual disease at the lateral margin and also revealed occult DCIS not found on biopsy. Additional tissue was taken until margin clearance by WF-OCT. Permanent histology demonstrated DCIS to &lt;1 mm of primary lateral margin; the additional excision contained DCIS and was margin negative. Conclusions: In this case series of 3 adult females undergoing BCS for breast carcinoma, WF-OCT was a beneficial adjunctive imaging modality to specimen radiography for margin assessment.
Citation Format: Amelia B. Tower, Andrew Berkeley. Use of wide field optical coherence tomography (WF-OCT) in margin assessment during breast conserving surgery (BCS) for ductal carcinoma in situ (DCIS) [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr B021.