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OC-053 Lectin-Based Near infra-red Molecular Imaging for Dysplasia Detection in Barrett’s Oesophagus: An ex-vivo Study on Human Tissue
  1. M Di Pietro1,
  2. A Neves2,
  3. M O’Donovan3,
  4. D Waterhouse4,
  5. S Bohndiek4,
  6. K Brindle2,
  7. RC Fitzgerald1
  1. 1MRC Cancer Unit
  2. 2Cancer Research UK Cambridge Institute, University of Cambridge
  3. 3Histopathology, Cambridge University Hospitals
  4. 4Department of Physics, University of Cambridge, Cambridge, UK

Abstract

Introduction Detection of early neoplasia in Barrett’s oesophagus (BO) by white-light endoscopy is challenging due to the inconspicuous nature of dysplasia. Molecular imaging using fluorescently labelled wheat-germ agglutinin (WGA) is a promising tool as this topically applied imaging agent shows lower binding to dysplastic versus non-dysplastic BO.1 However in an endoscopy setting, the detection of fluorescence in the blue/green range is limited by high-levels of tissue autofluorescence. This limitation can be overcome by using near infra-red (NIR) imaging. We aimed to assess in an ex-vivo model the feasibility of WGA-based NIR imaging for detection of dysplasia in BO.

Methods we recruited patients with early BO-related neoplasia undergoing endoscopic mucosal resection (EMR). Freshly collected EMR specimens were sprayed with WGA-IR800CW and then imaged with a high-sensitivity NIR camera. Fluorescence images were captured and up to two punch biopsies were collected from each EMR under fluorescence guidance. The EMRs were paraffin embedded, cut every 2 mm and processed for histopathological assessment. Each section was scored by an expert GI pathologist every 1 mm to construct a pathology grid, which was manually co-registered with the fluorescence image. The mean fluorescence intensity (MFI) of cells in dysplastic and non-dysplastic areas was compared by the Wilcoxon matched-pairs signed rank test. Only EMR specimens with at least one dysplastic gland were included in the analysis. In addition, the MFI of punch biopsies taken from dysplastic and non-dysplastic areas was also compared by Mann-Whitney test.

Results Ten patients were recruited at a single centre. A total of 18 EMR specimens and 33 punch biopsies were collected, of which 10 were dysplastic. In the whole EMR analysis, we found a significantly lower MFI for dysplastic versus non-dysplastic areas (P = 0.0012), in accordance with the reported reduced binding of WGA to neoplastic BO epithelium. Similarly, we found a nearly 2 fold reduction in the MFI of punch biopsies taken from dysplastic as compared to non-dysplastic (ND) areas (P = 0.0002) (Figure 1).

Conclusion WGA-based NIR imaging is an effective method for differentiating dysplastic from non-dysplastic BO mucosa ex vivo, which reduces the effects of tissue autofluorescence. In-vivo studies are now required to test the efficacy of this method for detecting dysplasia during endoscopic surveillance.

Reference 1 Bird-Lieberman, et al. Nat Med 2012.

Disclosure of Interest None Declared

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