Current standard-of-care for breast conserving surgery (BCS) procedures relies on post-operative histopathology to provide a microscopic view and assessment of surgical margins. To avoid high reoperation rates there has been a great interest in developing new imaging solutions to visualize tissue intraoperatively, and provide real-time feedback on the margin status. Optical coherence tomography (OCT) is a high-resolution label-free, imaging technology that is the optical analogue to ultrasound imaging, except images are based on backscattered near-infrared light. Fundamentally, the contrast mechanism of OCT relies on the light scattering properties associated with different tissue structures. Unlike normal tissue with well-organized tissue structure, the structure of cancer tissue is often disorganized and typically characterized by variable cell sizes, abnormal shapes, and enlarged nuclei, resulting in different optical scattering properties, and enabling OCT to reveal differences between normal and cancerous tissues with high spatial resolution. We have previously demonstrated OCT for in vivo label-free intraoperative assessment of the breast conserving surgery (BCS) with a hand-held OCT probe that is integrated with a portable OCT system. Despite the technological advance to achieve in vivo OCT imaging during BCS, there remains a critical need to improve the OCT-based detection, differentiation, and diagnosis of breast tumor tissue.
Polarization-sensitive optical coherence tomography (PS-OCT) is a functional extension of standard OCT that maps changes in the polarization state of light induced by anisotropic tissue properties. By exploiting the interaction between the polarization state of light and tissue, additional structural and functional information can be extracted. Form birefringence is the main optical property present in tissues responsible for altering the polarization state of light. In breast tissue, birefringent structures include the connective tissue or normal stroma, composed largely of collagen fibers. In the presence of breast cancer, the birefringent collagen fibers are degraded, displaced, reorganized, and/or disrupted in ways that dramatically alter the PS-OCT signal, serving as a fundamentally new optical imaging biomarker for the presence of cancer in the breast.
In this study, we report data from 23 cancer surgeries, compared with healthy breast tissue samples obtained from the breast reduction surgeries. Our results show strong correlation of observed tissue birefringence and collagen fiber density, and the lack of the tissue birefringence, due to low collagen fiber density, in the cancerous areas. Our PS-OCT imaging system provides faster and more informative intraoperative tumor margin assessment. It has the potential to determine margin status in real-time during the surgical procedure and reduce reoperation rates.
Citation Format: Marina Marjanovic, Jianfeng Wang, Yang Xu, Eric J. Chaney, Darold R. Spillman, Anna M. Higham, Natasha N. Luckey, Kimberly A. Cradock, George Z. Liu, Stephen A. Boppart. Intraoperative breast cancer margin detection via polarization-sensitive optical coherence tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3038.