Towards intraoperative assessment of tumor margins in breast surgery using optical coherence elastography (Conference Presentation)

Abstract

Surgical excision of tumor is a critical factor in the management of breast cancer. The most common surgical procedure is breast-conserving surgery. The surgeon’s goal is to remove the tumor and a rim of healthy tissue surrounding the tumor: the surgical margin. A major issue in breast-conserving surgery is the absence of a reliable tool to guide the surgeon in intraoperatively assessing the margin. A number of techniques have been proposed; however, the re-excision rate remains high and has been reported to be in the range 30-60%. New tools are needed to address this issue. Optical coherence elastography (OCE) shows promise as a tool for intraoperative tumor margin assessment in breast-conserving surgery. Further advances towards clinical translation are limited by long scan times and small fields of view. In particular, scanning over sufficient areas to assess the entire margin in an intraoperative timeframe has not been shown to be feasible. Here, we present a protocol allowing ~75% of the surgical margins to be assessed within 30 minutes. To achieve this, we have incorporated a 65 mm-diameter (internal), wide-aperture annular piezoelectric transducer, allowing the entire surface of the excised tumor mass to be automatically imaged in an OCT mosaic comprised of 10 × 10 mm tiles. As OCT is effective in identifying adipose tissue, our protocol uses the wide-field OCT to selectively guide subsequent local OCE scanning to regions of solid tissue which often present low contrast in OCT images. We present promising examples from freshly excised human breast tissue.